Visual Studio 2008 and .NET 3.5 Using C# · Visual Studio 2008 and .NET 3.5 Using C# Rev. 1.0 Student Guide ... extensively with .NET 3.5 applications. NewCs3 Chapter 1 ... capabilities

Object Innovations Course 4010

Student Guide Revision 1.0

Visual Studio 2008 and .NET 3.5 Using C#

Rev. 1.0 Copyright ©2008 Object Innovations Enterprises, LLC ii All Rights Reserved

Visual Studio 2008 and .NET 3.5 Using C# Rev. 1.0 Student Guide Information in this document is subject to change without notice. Companies, names and data used in examples herein are fictitious unless otherwise noted. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical, for any purpose, without the express written permission of Object Innovations. Product and company names mentioned herein are the trademarks or registered trademarks of their respective owners. Authors: Robert J. Oberg and Julian Templeman Copyright ©2008 Object Innovations Enterprises, LLC All rights reserved. Object Innovations 877-558-7246 www.objectinnovations.com Published in the United States of America.

Rev. 1.0 Copyright ©2008 Object Innovations Enterprises, LLC iii All Rights Reserved

Table of Contents (Overview) Chapter 1 Visual Studio 2008 Chapter 2 New Features in C# 3.0 Chapter 3 Language-Integrated Query (LINQ) Chapter 4 Windows Communication Foundation (WCF) Chapter 5 Windows Workflow Foundation (WF) Chapter 6 Windows Presentation Foundation (WPF) Appendix A Learning Resources

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Directory Structure

• Install the course software by running the self-extractor Install_NewCs3_10.exe.

• The course software installs to the root directory c:\OIC\NewCs3.

− Example programs for each chapter are in named subdirectories of chapter directories Chap01, Chap02 and so on.

− The Labs directory contains one subdirectory for each lab, named after the lab number. Starter code is frequently supplied, and answers are provided in the chapter directories.

− The Demos directory is provided for performing in-class demonstrations led by the instructor.

• Data files install to the directory c:\OIC\Data.

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Table of Contents (Detailed)

Chapter 1: Visual Studio 2008............................................................................................. 1 Overview of .NET Framework 3.0 ..................................................................................... 3 .NET 3.0 Block Diagram .................................................................................................... 4 .NET Framework 3.5 .......................................................................................................... 5 Visual Studio 2008.............................................................................................................. 6 Visual Studio 2008 Versions .............................................................................................. 7 Visual Studio 2008 Team System....................................................................................... 8 Plan for this Course............................................................................................................. 9 A Tour of Visual Studio 2008........................................................................................... 10 New WPF Project Templates............................................................................................ 11 Creating a New WPF Application .................................................................................... 12 XAML............................................................................................................................... 13 Navigating XAML and Design View ............................................................................... 14 Sample Application........................................................................................................... 15 Editing XAML.................................................................................................................. 16 Sizing the Window............................................................................................................ 19 Adding an Event Handler ................................................................................................. 21 Solutions with Multiple Projects....................................................................................... 23 Class Library Project Demo.............................................................................................. 24 Referencing the Class Library .......................................................................................... 25 Referencing the Class Library .......................................................................................... 26 Project Dependencies........................................................................................................ 27 Build Order ....................................................................................................................... 28 Using the Class Library .................................................................................................... 29 New Web Project Templates ............................................................................................ 30 Reporting Project Templates ............................................................................................ 31 WCF Project Templates.................................................................................................... 32 Workflow Project Templates ............................................................................................ 33 Workflow Designer........................................................................................................... 34 Object/Relational Designer............................................................................................... 35 Lab 1 ................................................................................................................................. 36 Summary ........................................................................................................................... 37

Chapter 2: New Features in C# 3.0 ................................................................................... 43 Auto-Implemented Properties........................................................................................... 45 Auto-Implemented Property Example .............................................................................. 46 Implicitly Typed Variables ............................................................................................... 47 Implicitly Typed Variables – Example ............................................................................. 48 Object Initializers.............................................................................................................. 49 Collection Initializers........................................................................................................ 50 Anonymous Types ............................................................................................................ 51

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Partial Methods ................................................................................................................. 52 Partial Method Definition ................................................................................................. 53 Partial Method Implementation ........................................................................................ 54 Main Program ................................................................................................................... 55 Running the Example........................................................................................................ 56 Extension Methods ........................................................................................................... 57 Extension Methods Example ............................................................................................ 58 Lambda Expressions ......................................................................................................... 59 Named Method.................................................................................................................. 60 Anonymous Method.......................................................................................................... 61 Lambda Expression Example ........................................................................................... 62 Language-Integrated Query (LINQ)................................................................................. 63 LINQ Example.................................................................................................................. 64 Using IEnumerable<T> .................................................................................................... 65 Lab 2 ................................................................................................................................. 66 Summary ........................................................................................................................... 67

Chapter 3: Language-Integrated Query (LINQ)............................................................. 73 What Is LINQ?.................................................................................................................. 75 Bridging Objects and Data................................................................................................ 76 LINQ Demo ...................................................................................................................... 77 Object Relational Designer ............................................................................................... 79 IntelliSense........................................................................................................................ 81 Basic LINQ Query Operators ........................................................................................... 82 Obtaining a Data Source ................................................................................................... 83 Basic Query Example ....................................................................................................... 84 Commands ........................................................................................................................ 86 Projection .......................................................................................................................... 87 Filtering............................................................................................................................. 88 Ordering ............................................................................................................................ 89 Grouping ........................................................................................................................... 90 Aggregation ...................................................................................................................... 92 Obtaining Lists and Arrays ............................................................................................... 93 Deferred Execution ........................................................................................................... 94 Inserts................................................................................................................................ 95 Deletes and Updates.......................................................................................................... 96 LINQ Data Stores ............................................................................................................. 97 LINQ to Objects................................................................................................................ 98 LINQ to ADO.NET .......................................................................................................... 99 Creating the Object Model.............................................................................................. 100 Demo: Using SQLMetal ................................................................................................. 101 DataContext .................................................................................................................... 102 Performing Inserts via LINQ to SQL.............................................................................. 103 Performing Deletes via LINQ to SQL ............................................................................ 104 Performing Updates via LINQ to SQL ........................................................................... 105 Lab 3A ............................................................................................................................ 106

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LINQ to DataSet ............................................................................................................. 107 LINQ to DataSet Demo .................................................................................................. 108 Using the Typed DataSet ................................................................................................ 110 Full-Blown LINQ to DataSet Example........................................................................... 111 LINQ to XML................................................................................................................. 112 Creating an XML Document .......................................................................................... 113 Querying and Modifying ................................................................................................ 115 Querying and Modifying Example ................................................................................. 116 Removing and Updating ................................................................................................. 117 Lab 3B............................................................................................................................. 118 Summary ......................................................................................................................... 119

Chapter 4: Windows Communication Foundation (WCF)........................................... 131 What Is WCF?................................................................................................................. 133 WCF Services ................................................................................................................. 134 Service Orientation ......................................................................................................... 136 WCF and Web Services .................................................................................................. 137 WCF = ABC ................................................................................................................... 138 Address, Binding, Contract............................................................................................. 139 Example – Hello WCF.................................................................................................... 140 Hosting Services ............................................................................................................. 141 Demo – Hello WCF ........................................................................................................ 142 Testing the Service.......................................................................................................... 144 Implementing the Host.................................................................................................... 146 A Client Program ............................................................................................................ 149 Data Contracts................................................................................................................. 151 Data Contract Example ................................................................................................... 152 Testing the Service Library............................................................................................. 154 Host ................................................................................................................................. 155 Client............................................................................................................................... 156 Adding a Service Reference ........................................................................................... 157 WCF Architecture........................................................................................................... 160 WCF Architecture........................................................................................................... 161 Addresses ........................................................................................................................ 162 Transports ....................................................................................................................... 163 Bindings .......................................................................................................................... 164 Message Exchange Patterns (MEPs) .............................................................................. 166 Security ........................................................................................................................... 167 Lab 4 ............................................................................................................................... 168 Summary ......................................................................................................................... 169

Chapter 5: Windows Workflow Foundation (WF)........................................................ 179 What Is Workflow?......................................................................................................... 181 Windows Workflow Foundation..................................................................................... 182 Workflows....................................................................................................................... 183 Activities ......................................................................................................................... 184

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Standard Activities.......................................................................................................... 185 Runtime Services ............................................................................................................ 186 Workflow Business Scenario.......................................................................................... 187 High Level Workflow..................................................................................................... 188 Details of While Activity ................................................................................................ 189 Orders Folder .................................................................................................................. 190 Manual Step in the Verification...................................................................................... 191 Main Console Display .................................................................................................... 192 Issues Folder ................................................................................................................... 193 Invoices Folder ............................................................................................................... 194 Learning Microsoft’s WF ............................................................................................... 195 Hello Workflow .............................................................................................................. 196 Hello Workflow Demo ................................................................................................... 197 IfElseActivity.................................................................................................................. 202 Implementing a Branch................................................................................................... 203 While Activity................................................................................................................. 205 High-Level Workflow..................................................................................................... 206 Sequence Activity ........................................................................................................... 207 Condition in While Activity ........................................................................................... 208 Parallel Activity .............................................................................................................. 209 Parallel Activity Workflow Diagram.............................................................................. 210 Lab 5 ............................................................................................................................... 211 Summary ......................................................................................................................... 212

Chapter 6: Windows Presentation Foundation (WPF) ................................................. 217 WPF and .NET Framework 3.5 ...................................................................................... 219 Core Types and Infrastructures....................................................................................... 220 XAML............................................................................................................................. 221 Controls........................................................................................................................... 222 Data Binding ................................................................................................................... 223 Appearance ..................................................................................................................... 224 Layout and Panels ........................................................................................................... 225 Graphics .......................................................................................................................... 226 Media .............................................................................................................................. 227 Documents and Printing.................................................................................................. 228 Application and Window ................................................................................................ 229 FirstWpf Example Program ............................................................................................ 230 Using a Button ................................................................................................................ 231 Device-Independent Pixels ............................................................................................. 232 Class Hierarchy............................................................................................................... 233 Content Property ............................................................................................................. 234 Handling an Event .......................................................................................................... 235 What Is XAML? ............................................................................................................. 236 Default Namespace ......................................................................................................... 237 Elements and Attributes.................................................................................................. 238 XAML in Visual Studio 2008......................................................................................... 239

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Demo: One Button via XAML ....................................................................................... 240 Panels .............................................................................................................................. 245 Layout in WPF................................................................................................................ 246 Controlling Size .............................................................................................................. 247 Margin and Padding........................................................................................................ 248 Thickness Structure......................................................................................................... 249 Children of Panels........................................................................................................... 250 Example – TwoControls ................................................................................................. 251 TwoControls – XAML.................................................................................................... 252 Automatic Sizing ............................................................................................................ 253 TwoControls – Code ....................................................................................................... 254 Orientation ...................................................................................................................... 255 Items Controls................................................................................................................. 256 Selector Controls............................................................................................................. 257 Using a ListBox .............................................................................................................. 258 Storing Objects in List Controls ..................................................................................... 259 Grid ................................................................................................................................. 260 Customizing a Grid ......................................................................................................... 261 GroupBox and RadioButton Controls............................................................................. 263 BankGrid Example.......................................................................................................... 264 Lab 6A ............................................................................................................................ 265 Menus in WPF ................................................................................................................ 266 Menu Controls ................................................................................................................ 267 Menu and Dialogs Example............................................................................................ 268 File Menu........................................................................................................................ 269 The Menu Using XAML................................................................................................. 270 Handling the Click Event................................................................................................ 271 Closing a Form................................................................................................................ 272 Other Controls on Menus................................................................................................ 273 Dialog Boxes in WPF ..................................................................................................... 274 MessageBox.................................................................................................................... 275 MessageBox Show Method ............................................................................................ 276 Common Dialog Boxes................................................................................................... 277 FileOpen Example .......................................................................................................... 278 FileOpen Example Code ................................................................................................. 279 Custom Dialogs............................................................................................................... 280 Modal Dialogs................................................................................................................. 281 Modal Dialog Example ................................................................................................... 282 XAML for New Item Dialog .......................................................................................... 283 Code for New Item Dialog.............................................................................................. 284 Bringing up the Dialog ................................................................................................... 285 Lab 6B............................................................................................................................. 286 Summary ......................................................................................................................... 287

Appendix A: Learning Resources.................................................................................... 303

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NewCs3 Chapter 1

Rev. 1.0 Copyright © 2008 Object Innovations Enterprises, LLC 1 All Rights Reserved

Chapter 1

Visual Studio 2008

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Visual Studio 2008

Objectives

After completing this unit you will be able to:

• Outline the features of .NET 3.0.

• Describe the additional capabilities of .NET 3.5.

• Explain the role of Visual Studio 2008 in providing tooling support for .NET 3.5 applications.

• List the versions of Visual Studio 2008 and understand which version is appropriate for specific tasks.

• Describe the new project templates and designers in Visual Studio 2008.

• Implement simple WPF programs by editing XAML markup and using the WPF Designer.

• Create multiple-project solutions, which are used extensively with .NET 3.5 applications.

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Overview of .NET Framework 3.0

• The Microsoft .NET Framework 3.0 (formerly called WinFX) introduced a new managed code programming model for Windows.

• NET Framework 3.0 includes .NET Framework 2.0 along with API’s for four new technologies.

− Windows Presentation Foundation (WPF, formerly “Avalon”) is a unified programming model for user interfaces, graphics, documents and media.

− Windows Communications Foundation (WCF, formerly “Indigo”) is a unified programming model to build service-oriented architecture (SOA) applications on the Windows platform.

− Windows Workflow Foundation (WF) is a programming model, engine and tools for building workflow applications on the Windows platform.

− Windows CardSpace (WCS, formerly “InfoCard”) is a new set of Windows technologies that provides a standards-based solution for managing digital identities.

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.NET 3.0 Block Diagram

• .NET Framework 3.0 layers on top of .NET Framework 2.0 and has the components shown in the diagram.

WindowsPresentationFoundation

(WPF)

WindowsCommunication

Foundation(WCF)

WindowsWorkflow

Foundation(WF)

WindowsCardSpace

(WCS)

.NET Framework 2.0

WindowsForms ASP.NET ADO.NET

Base Class Libraries

Common Language Runtime

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.NET Framework 3.5

• The .NET Framework 3.5 adds a number of important features beyond those of .NET 3.0.

− Perhaps the most important is integration with the tooling support provided by Visual Studio 2008, which we’ll discuss later in the chapter.

• Language Integrated Query (LINQ) extends query capabilities to the syntax of the C# and Visual Basic programming languages.

− The technology can be extended to almost any data store, and out of the box includes support for objects, the file system, SQL Server and XML.

• Enhancements to the C# programming language, largely to support LINQ.

• Integration of ASP.NET AJAX into the .NET Framework.

• Many other enhancements, including:

− A powerful Add-In infrastructure

− Peer-to-peer networking support

− Integration of WCF and WF

− Enhancements to both WPF and Windows Forms

− Enhancements to ASP.NET, including new controls and a Web Application project.

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Visual Studio 2008

• Visual Studio 2008 provides effective tooling support for .NET Framework 3.5.

− Although .NET 3.0 add-ins for Visual Studio 2005 were available, full tool support only comes with Visual Studio 2008.

• Enhancements in Visual Studio 2008 include:

− Improvements in the Integrated Development Environment (IDE), such as better navigation and easier docking.

− Automatic settings migration from Visual Studio 2005 (but third-party add-ons must be manually migrated).

− Multi-targeting to .NET 2.0, .NET 3.0 or .NET 3.5.

• There are many new project templates:

− ASP.NET AJAX projects

− WPF projects

− WCF projects

− WF projects

− Reporting projects

• There are a number of new designers, including WPF Designer, an object/relational designer, and a workflow designer.

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Visual Studio 2008 Versions

• The Express Editions provides a lightweight IDE, with separate versions for C#, Visual Basic, Visual C++, and for Web application development.

− These versions provide a simplified environment and are permanently free.

• Visual Studio 2008 Standard Edition provides a fully integrated environment for all the supported languages and project types.

− Numerous additional features are provided for debugging, refactoring, XML programming, WCF development, and other tasks.

− It provides most of the features of the Professional Edition at a lower price point.

− Everything covered in this course works fine with the Standard Edition.

− Visual Studio 2008 Professional Edition supports development for a wider range of platforms, including Microsoft Office, smart devices, and Windows CE.

− It also includes automated support for unit testing.

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Visual Studio 2008 Team System

• Visual Studio 2008 Team System contains numerous tools for Application Lifecycle Management (ALM).

• There are four versions, supporting specific development roles in large projects.

− Architecture Edition

− Database Edition

− Development Edition

− Test Edition

• Team Suite is a bundle containing all four editions of Team System.

• Visual Studio 2008 Team Foundation Server is the collaboration server at the hub of the whole Team System, including support of:

− Project management

− Work item tracking

− Version control

− Reporting and business intelligence

− Build management

− Process guidance

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Plan for this Course

• The scope of .NET 3.5 and Visual Studio 2008 is daunting!

− There is no way we can do justice to this rich technology in just three days.

• Our plan is to cover some of the most important topics in a hands-on manner.

− In the rest of this chapter we’ll take a brief tour of Visual Studio 2008, including a first look at WPF.

− In Chapter 2 we’ll cover the new language features in C#.

− Chapter 3 introduces LINQ.

− Chapter 4 introduces WCF.

− Chapter 5 introduces WF.

− Chapter 6 gives a substantial introduction to WPF.

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A Tour of Visual Studio 2008

• Visual Studio 2008 opens up with an appearance very similar to Visual Studio 2005.

• Our tour will include the following:

− New project templates

− Some of the new designers

− Creating a simple solution with two projects, a WPF Windows application and a class library.

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New WPF Project Templates

• Bring up the New Project dialog:

− File | New Project.

• You’ll see four new templates for Visual C# Windows project type.

− WPF Application

− WPF Custom Control Library

− WPF Browser Application

− WPF User Control Library

− Note the dropdown at top specifying target .NET version.

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Creating a New WPF Application

• As illustrated on the preceding page, let’s create a new WPF Application.

1. Select the WPF Application template.

2. Navigate to the \OIC\NewCs3\Demos directory.

3. Type in HelloWpf as the name of the new project.

4. Check “Create directory for solution” and click OK.

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XAML

• The most conspicuous new feature is a split window, showing XAML markup language in the lower pane and a visual design view in the upper pane.

• Extensible Application Markup Language (XAML, pronounced “zammel”) provides a declarative way to define user interfaces.

− The topmost UI element is Window, which is shown highlighted in the XAML pane and selected in the Property window.

− Change the Title to “Hello WPF”.

− The new title is now shown in both XAML and the design view.

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Navigating XAML and Design View

• A tabbed UI with various buttons lets you switch between Design and XAML view.

• The button collapses to a single view. You can select which single view you want displayed by selecting the Design or XAML tab.

• You can go back to horizontal split with the button and to a vertical split with the button.

• You can flip the two views with the tab.

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Sample Application

• As a demo we’re going to create a simple WPF Windows application.

− User enters name.

− User clicks Greet button.

− A message box appears with a greeting.

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Editing XAML

• The UI can be completely specified in the text XAML file and edited as text.

• Continuing with the HelloWpf application we’ve created in the Demos directory, do the following:

1. Collapse to just the XAML view.

2. Change the <Grid> to <StackPanel>, a simpler kind of panel.

3. Within the <StackPanel> provide a <WrapPanel>. Note how IntelliSense makes your entry easier.

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Editing XAML (Cont’d)

4. After you select <WrapPanel> from the yellow IntelliSense popup, type a closing > and you’ll see the following XAML code.

<StackPanel> <WrapPanel> </WrapPanel> </StackPanel> 5. Now enter a <Label> and a <TextBox>, providing a suitable

Name attribute for the text box.

<StackPanel> <WrapPanel> <Label>Name:</Label> <TextBox Name="txtName"/> </WrapPanel> </StackPanel> 6. Next, after the <WrapPanel> provide a <Button>.

<StackPanel> <WrapPanel> <Label>Name:</Label> <TextBox Name="txtName"/> </WrapPanel> <Button Name="btnGreet">Greet</Button> </StackPanel>

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Sizing the Elements

7. Switch to Design view. Some tweaking is required!

8. Drag the text box wider. Note that the window, panels, and button also expand.

9. Drag the button to be more narrow.

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Sizing the Window

10. Build and run your little app. The main window opens to a default size, which is not what you want!

11. Back in Design View, nudge the size of the window a little in each dimension.

12. Now build and run again. Better!

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Editing XAML (Cont’d)

13. Back in XAML view, place margins around the wrap panel and button. Also, provide a Background for the window. You can choose a color with the help of IntelliSense.

<Window ... Title="Hello WPF" Height="111" Width="187" Background="Beige"> <StackPanel> <WrapPanel Margin="10"> <Label>Name:</Label> <TextBox Name="txtName" Width="126" /> </WrapPanel> <Button Name="btnGreet" Width="62" Margin="10">Greet</Button> </StackPanel> </Window> 14. Back in Design view, the margin has thrown off the sizing of

the window. Resize the window again.

15. Back in XAML view, you can see the new dimensions of the window.

<Window ... Title="Hello WPF" Height="122" Width="216" Background="Beige"> ...

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Adding an Event Handler

16. Finally, we’ll provide a handler for the Click event of the button. In XAML you can use IntelliSense to find the Click event.

17. Selecting the Click event, you are now able to add a new event handler.

18. Here is the XAML after the event handler has been added:

<Button Name="btnGreet" Width="62" Margin="10" Click="btnGreet_Click">Greet</Button> 19. A stub for the event handler is generated in the “code behind”

file Window1.xaml.cs.

private void btnGreet_Click(object sender, RoutedEventArgs e) { }

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Adding an Event Handler (Cont’d)

20. Provide the following code to retrieve the name entered in the text box and use it to display a greeting in a message box.

private void btnGreet_Click(object sender, RoutedEventArgs e) { MessageBox.Show("Hello, " + txtName.Text, "Hello WPF"); } 21. Build and run. We’ve completed the application we set out to

create!

• The application at this point is saved in the Chap01 folder.

− See \OIC\Chap01\HelloWpf\Step1.

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Solutions with Multiple Projects

• Visual Studio makes it easy to manage solutions with multiple projects.

− We’ll use this feature extensively in later chapters.

• As a small demo, let’s create a class library GreetLib with a method GetGreeting() that returns a greeting.

1. In Solution Explorer, right-click over the solution and select Add | New Project ... from the context menu.

2. The Add New Project dialog comes up. Choose ClassLibrary as the template, and type in GreetLib as the name of your new class library.

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Class Library Project Demo

3. In Solution Explorer, change the name of the file Class1.cs to Greet.cs. Note that the name of the class changes too.

4. Provide the following code for a static method GetGreeting().

using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace GreetLib { public class Greet { public static string GetGreeting(string name) { return "Hello, " + name; } } }

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Referencing the Class Library

5. To use this class library from the HelloWpf project, we’ll need to add a reference.

6. Right-click over References and choose Add Reference ... from the context menu. (Add Service Reference ... is a new feature in Visual Studio 2008 and refers to a WCF service.)

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Referencing the Class Library

7. In the Add Reference dialog select the Projects tab. Note that the GreetLib project has been selected for you.

8. Click OK.

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Project Dependencies

9. Add a project reference in this way automatically sets up correct project dependencies. To see this, right-click on the solution and select Project Dependencies ... from the context menu.

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Build Order

10. The build order is right too.

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Using the Class Library

11. To simplify using the class library in the file Window1.xaml.cs, we provide a using statement for GreetLib.

... using System.Windows.Navigation; using System.Windows.Shapes; using GreetLib; 12. Finally, we modify the code in the event handler to call the

static GetGreeting() method.

private void btnGreet_Click(object sender, RoutedEventArgs e) { MessageBox.Show(Greet.GetGreeting(txtName.Text), "Hello WPF"); } 13. Build the solution. This will build both projects, the class

library first.

14. Run the program. The first project in the solution, HelloWpf, is by default the startup project, so HelloWpf.exe will run. The program should behave the same as before.

• The program is now at Step 2.

− See Chap01\HelloWpf\Step2.

− You’ll create a Step 3 in a lab!

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New Web Project Templates

• Continuing our tour, there are three new Web project templates:

− ASP.NET AJAX Server Control

− ASP.NET AJAX Server Control Extender

− WCF Service Application

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Reporting Project Templates

• There is a new Reporting project type with this template:

− Reports Application.

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WCF Project Templates

• WCF is another new project type, with these templates:

− Sequential Workflow Service Library

− Syndication Service Library

− State Machine Workflow Service Library

− WCF Service Library

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Workflow Project Templates

• Finally, a new Workflow project type has six templates:

− Empty Workflow Project

− Sequential Workflow Library

− State Machine Workflow Library

− Sequential Workflow Console Application

− State Machine Workflow Console Application

− Workflow Activity Library

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Workflow Designer

• Workflows can be visually created using the new Workflow Designer.

− Workflows will be discussed in Chapter 5.

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Object/Relational Designer

• Another new designer in Visual Studio 2008 is the Object/Relational Designer.

− This tool enables you to automatically create entity classes that represent the relational data your program interacts with.

− This tool will be discussed in Chapter 3.

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Lab 1

An Enhanced WPF Application and Class Library

In this lab you will enhance both the user interface and the class library in the HelloWpf solution. In the new version, the user will be able to choose a language for the greeting.

Detailed instructions are contained in the Lab 1 write-up at the end of the chapter.

Suggested time: 30 minutes

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Summary

• .NET 3.0, layered on .NET 2.0, introduced these technologies:

− Windows Presentation Foundation (WPF)

− Windows Communication Foundation (WCF)

− Windows Workflow Foundation (WF)

− Windows CardSpace (WCS)

• .NET 3.5 provides new language features in C# and Visual Basic and introduces Language Integrated Query (LINQ).

• Visual Studio 2008 provides tooling support for .NET 3.5 applications.

• Visual Studio 2008 comes in Express, Standard, Professional and Team System editions.

• Visual Studio 2008 provides new project templates and designers.

• You can implement WPF programs by editing XAML markup and using the WPF Designer.

• An important capability of Visual Studio is multiple-project solutions, which are used extensively with .NET 3.5 applications.

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Lab 1

An Enhanced WPF Application and Class Library

Introduction In this lab you will enhance both the user interface and the class library in the HelloWpf solution. In the new version, the user will be able to choose a language for the greeting.

Suggested Time: 30 minutes Root Directory: OIC\NewCs3 Directories: Labs\Lab1\HelloWpf (do your work here) Demos\HelloWpf (alternate working directory) Chap01\HelloWpf\Step2 (backup of starter code) Chap01\HelloWpf\Step3 (answer) A clean starting solution, backed up in Chap01\HelloWpf\Step2, is provided in the lab working directory. Alternatively, if you prefer, you may continue with your own work done in the Demos directory. Part 1. Enhance the User Interface In Part 1 we’ll add a dropdown combo box to let the user specify a choice of language for the greeting. 1. Build and run the starter program. Notice that if you make the window more narrow,

the text box “wraps” rather than becomes partially or totally obscured (as it would in a normal Windows Forms application).

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2. In XAML view add a <ComboBox> between the <WrapPanel> and the <Button>.

<StackPanel> <WrapPanel Margin="10"> <Label>Name:</Label> <TextBox Name="txtName" Width="126" /> </WrapPanel> <ComboBox> </ComboBox> <Button Name="btnGreet" Width="62" Margin="10" Click="btnGreet_Click">Greet</Button> </StackPanel> 3. In Design view adjust the size of both the window (you need to increase the height)

and the combo box (make it more narrow).

4. Select the combo box, and in the Properties window find the Items property.

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5. Click on the button. The Collection Item Editor comes up. Add three ComboBoxItem elements. Make the Content of these three items “English”, “French” and “Texan”.

6. Click OK, and examine the XAML markup.

<ComboBox Width="125"> <ComboBoxItem>English</ComboBoxItem> <ComboBoxItem>French</ComboBoxItem> <ComboBoxItem>Texan</ComboBoxItem> </ComboBox> 7. Build and run. Nothing is selected originally, but you can drop down the combo box

and select something, e.g. “English”.

8. To make “English” automatically selected as the default, you can set the IsSelected property to True. Also, assign the Name property of the combo box itself to cmbLanguage.

<ComboBox Width="125" Name="cmbLanguage"> <ComboBoxItem IsSelected="True">English</ComboBoxItem> <ComboBoxItem>French</ComboBoxItem>

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<ComboBoxItem>Texan</ComboBoxItem> </ComboBox> 9. Build and run, verifying that “English” is indeed shown as the default selection.

10. Temporarily show another message box in the handler of the Greet button to display the selected item.

private void btnGreet_Click(object sender, RoutedEventArgs e) { MessageBox.Show(cmbLanguage.SelectedItem.ToString()); MessageBox.Show(Greet.GetGreeting(txtName.Text), "Hello WPF"); } 11. Build and run, and click Greet. The result is disappointing.

12. The items in the combo box are stored as type object. To get what we want, we need to perform a cast to ComboBoxItem and take the Content property. Use this code instead:

private void btnGreet_Click(object sender, RoutedEventArgs e) { ComboBoxItem cbi = (ComboBoxItem)cmbLanguage.SelectedItem; MessageBox.Show(cbi.Content.ToString()); MessageBox.Show(Greet.GetGreeting(txtName.Text), "Hello WPF"); } 13. Build and run. Now we get what we want!

Part 2. Enhance the Class Library In Part 2 we’ll add a second method to the Greet class in the class library. This method will take a second string, the name of the language to be used in the greeting.. 1. In the GreetLib project, provide an overloaded version of the GetGreeting() method.

In the code, you simply test the value of the language parameter and return the appropriate greeting. Return an error message if the language is something unexpected.

public class Greet { public static string GetGreeting(string name)

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{ return "Hello, " + name; } public static string GetGreeting(string name, string lang) { if (lang == "English") return "Hello, " + name; else if (lang == "French") return "Bonjour, " + name; else if (lang == "Texan") return "Howdy, " + name; else return "Language not supported"; } 2. In the HelloWpf project, modify the code of the button handler to call this new

overloaded method. You may comment out showing the first message box.

private void btnGreet_Click(object sender, RoutedEventArgs e) { ComboBoxItem cbi = (ComboBoxItem)cmbLanguage.SelectedItem; //MessageBox.Show(cbi.Content.ToString()); string language = cbi.Content.ToString(); string greeting = Greet.GetGreeting(txtName.Text, language); MessageBox.Show(greeting, "Hello WPF"); } 3. Build and test. The program should now be fully operational!

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Chapter 5

Windows Workflow Foundation (WF)

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Windows Workflow Foundation (WF)

Objectives

After completing this unit you will be able to:

• Explain what a workflow is and how Windows Workflow Foundation supports workflow applications.

• Describe a typical business scenario for workflow and illustrate with a WF application.

• Create workflow applications using Visual Studio 2008 and the Workflow Designer.

• Explain what an activity is and use typical activities in your workflow applications:

− Code

− IfElse

− While

− Sequence

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What Is Workflow?

• In general terms, a workflow can be thought of as a flow of processes or tasks that produce some result.

• Workflows are often concerned with documents that flow through various activities and may spawn other documents as they are processed.

• Workflows can be manual, with paper documents being transmitted among people working at different desks in an office, each person performing defined tasks according to specified rules.

• We are concerned with workflows as software systems that define the flow of work, the activities performed, and the rules that are employed.

− Rules can be expressed declaratively or in code.

− Activities may be entirely automated or may involve human interaction.

− Workflows may be distributed among multiple computers in diverse locations.

− Workflows are typically represented in a graphical manner.

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Windows Workflow Foundation

• Windows Workflow Foundation (WF) is a framework that supports creating and running workflow applications on Windows platforms.

− WF consists of a programming model, an engine, and tools.

− The tools include designers for Visual Studio.

• WF provides a consistent development experience with other .NET 3.0/3.5 technologies, including WCF and WPF.

• The WF API contains support for both C# and Visual Basic, a special workflow compiler, workflow debugging support, and a visual workflow designer.

• Workflows can be developed completely in code or created in conjunction with XAML markup.

• The WF model and designer are extensible, enabling developers to create custom activities the encapsulate particular workflow functionality.

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Workflows

• A workflow is a set of activities that are stored in a model describing a business (or other real-world) process.

• A workflow describes the order of execution and relationships between units of work.

− The units of work may run for a short time or a long time.

− Activities may be performed by people or the computer.

• A workflow instance is created and maintained by the workflow runtime engine.

− There can be several workflow engines within an application domain.

− Each instance of the engine can support multiple workflow instances.

• A compiled workflow model can be hosted inside any Windows process, including a console application, a Windows Forms application, a WPF application, a Windows service, an ASP.NET Web application, and a Web service.

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Activities

• The units of work of a workflow are called activities.

• When a workflow instance starts, activities are executed in an order as defined by the workflow model.

− Both parallel and sequential orders of execution are supported.

− Conditional and looping behavior of activities is supported.

− Execution continues until the last activity completes, and the workflow then terminates.

• Activities can be reused within a workflow and in other workflows.

• Activities usually have properties that are configurable.

• WF provides many standard activities out-of-the box, and custom activities can be created.

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Standard Activities

• The Visual Studio toolbox contains many standard activities that can be dragged onto the surface of the Workflow Designer.

− The Code activity can be used to represent any desired

custom code.

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Runtime Services

• WF provides a number of out-of-the box runtime services that are available in the workflow engine.

• Persistence services enable a developer to easily save a WF instance to external storage, such as a database or XML file.

− This capability enables workflow applications to maintain state and be long-running, surviving application restarts.

• Transaction services enable you to maintain transactional integrity in workflow applications.

• Tracking services support monitoring and recording workflow execution.

• Scheduling services enable you to control how the WF runtime manages threads in your application.

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Workflow Business Scenario

• To illustrate workflows consider the following business scenario:

− As orders are created they are specified in XML files placed in the folder Orders.

− Each order in the Orders folder is processed, beginning with getting the order information from the XML file.

− The order is verified, which is done by a person who checks each item in the order for consistency (description furnished by customer matches the description in the vendor database or has a trivial error such as a misspelling). The system also does some verification, making sure that the item ID is found in the database.

− If the order is valid, it is processed and an invoice is created. The invoice is specified in an XML, stored in the Invoices folder.

− If the order is not valid, the issue with the order is specified in another XML file, stored in the Issues folder. (A customer service representative can follow up on such orders by emailing the customer.)

• This scenario is implemented by a workflow application.

− See Chap05\OrderWF. See the file Workflow1.cs in the OrderWF project for a diagram of the workflow.

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High Level Workflow

• Open up the file Workflow1.cs.

− The Workflow Designer opens up, showing a diagram of the workflow.

− Examine the workflow at a high level by collapsing the whileMoreOrders activity. (Where a portion of the diagram can be collapsed you will see a little button showing a minus sign that can be clicked.)

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Details of While Activity

• The heart of the workflow is a loop that gets and verifies orders.

− If order is valid, it is processed.

− If order is not valid, an issue is processed.

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Orders Folder

• The Orders folder contains XML files representing orders. The loop goes through all the files in this folder.

− As an example, consider 1002.xml. This order is basically valid, but one of the items is slightly questionable.

<?xml version="1.0" encoding="utf-8" standalone="yes"?> <Order> <OrderId>1002</OrderId> <Customer> <Name>Mary Smith</Name> <Email>[email protected]</Email> </Customer> <Item> <ItemId>104</ItemId> <Description>Sofa</Description> <Quantity>1</Quantity> </Item> <Item> <ItemId>102</ItemId> <Description>Tabel</Description> <Quantity>2</Quantity> </Item> <Item> <ItemId>103</ItemId> <Description>Lamp</Description> <Quantity>2</Quantity> </Item> </Order>

• An automated verification might reject item 102 because of the misspelling of the description.

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Manual Step in the Verification

• As is typical in workflow applications, steps in the workflow can be carried out either by the computer or a person.

• As part of the processing of the VerifyOrder activity a message box will be displayed for a human to verify each item.

• Build the solution, which consists of four projects.

− Start the Host project, which must be running because VerifyOrder invokes a WCF service.

− Then start the OrderWF project.

− As orders are verified, a message box will pop up for each item of each order.

• Here is the message box for item 102 of order 1002.

• The person viewing this will clearly see that this is benign and will click Yes to approve this item.

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Main Console Display

• As the workflow is executed, a running report on each item is displayed on a main console.

• Here is the display for order 1002: C:\OIC\NewCs3\Demos\OrderWF\Orders\1002.xml OrderId = 1002 Verification message = OK OrderId = 1002 CustomerName = Mary Smith CustomerEmail = [email protected] ItemId Description Quantity ... Price Extension 104 Sofa 1 ... $500.00 $500.00 102 Tabel 2 ... $200.00 $400.00 103 Lamp 2 ... $50.00 $100.00 Total = $1,000.00 File 1002.xml has been created in folder Invoices

• And here is the display for orders 1003 and 1004 for which there were genuine issues.

file = 1003.xml C:\OIC\NewCs3\Demos\OrderWF\Orders\1003.xml OrderId = 1003 Verification message = Description does not match Create issue: Description does not match File 1003.xml has been created in folder Issues file = 1004.xml C:\OIC\NewCs3\Demos\OrderWF\Orders\1004.xml OrderId = 1003 Verification message = Item Not Found Create issue: Item Not Found File 1004.xml has been created in folder Issues Press Enter to exit

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Issues Folder

• The Issues folder will contain an XML file for each order having a genuine issues.

• Our example illustrates two kinds of problems.

− The item is not found in the database, a problem that can be detected automatically, illustrated in order 1004.

− The item’s description indicates a genuine question, such as an ambiguity that should be verified with the customer, illustrated in order 1003.

− The human verifier will reject this item, because the company has several bookshelves having different numbers of shelves, and the customer should be queried to make sure she gets the desired bookshelf.

− Here is the generated issue file 1003.xml: <?xml version="1.0" encoding="utf-8" standalone="yes"?> <Issue> <OrderId>1003</OrderId> <CustomerName>Bill Jones</CustomerName> <CustomerEmail>[email protected]</CustomerEmail> <Message>Description does not match</Message> </Issue>

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Invoices Folder

• For valid orders an XML file is created from which an invoice can be generated.

− The actual invoice that will be sent to the printer is created by a separate subsystem, which could be another workflow, whose input is the files in the Invoices folder.

• As an example, here is the invoice XML file for order 1002.

<?xml version="1.0" encoding="utf-8" standalone="yes"?> <Invoice> <OrderId>1002</OrderId> <CustomerName>Mary Smith</CustomerName> <CustomerEmail>[email protected]</CustomerEmail> <LineItem> <ItemId>104</ItemId> <Description>Sofa</Description> <Quantity>1</Quantity> <Price>500.0000</Price> <Extension>500.0000</Extension> </LineItem> <LineItem> <ItemId>102</ItemId> <Description>Table</Description> <Quantity>2</Quantity> <Price>200.0000</Price> <Extension>400.0000</Extension> </LineItem> <LineItem> <ItemId>103</ItemId> <Description>Lamp</Description> <Quantity>2</Quantity> <Price>50.0000</Price> <Extension>100.0000</Extension> </LineItem> <Total>1000.0000</Total> </Invoice>

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Learning Microsoft’s WF

• There are two main challenges in learning to use Windows Workflow Foundation.

• The first challenge is to understand the nature of workflow applications, which are quite different in structure from conventional applications.

− For this purpose studying a miniature example illustrating an actual business scenario is invaluable.

− The program OrderWF is such an example.

• The second challenge is to understand the classes and tools in the actual framework.

− For this purpose studying small standalone examples, divorced from the complexities of a business situation, will be most helpful.

− We’ll follow this approach in the remainder of the chapter, beginning with a simple “Hello Workflow” example that we will build from scratch using Visual Studio 2008.

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Hello Workflow

• Let’s use Visual Studio 2008 to create a simple workflow that will do the following:

− Prompt the user for a name.

− Display a greeting.

− Prompt for exit.

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Hello Workflow Demo

1. In Visual Studio create a new project of type Workflow using the Sequential Workflow Console Application template. Provide the Name HelloWF and location C:\OIC\NewCs3\Demos.

2. In Solution Explorer, change the name of the file Workflow1.cs to GreetingWorkflow.cs and click the View Code button.

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Hello Workflow Demo (Cont’d)

3. Examine the starter code:

using System; using System.ComponentModel; using System.ComponentModel.Design; using System.Collections; using System.Drawing; using System.Linq; using System.Workflow.ComponentModel.Compiler; using System.Workflow.ComponentModel.Serialization; using System.Workflow.ComponentModel; using System.Workflow.ComponentModel.Design; using System.Workflow.Runtime; using System.Workflow.Activities; using System.Workflow.Activities.Rules; namespace HelloWF { public sealed partial class GreetingWorkflow: SequentialWorkflowActivity { public GreetingWorkflow() { InitializeComponent(); } } }

− The key class is SequentialWorkflowActivity in the System.Workflow.Activities namespace.

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4. Click the View Designer button.

5. Examine the starter workflow in the Workflow Designer.

6. Drop a Code activity between the start and end icons. In the Properties window, change the Name to PromptForName.

7. The exclamation point icon indicates that this activity has not yet been completely specified. You need to specify the ExecuteCode property.

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8. Name the method PromptForUserName. (It has to be different from the name of the activity.)

9. You will be brought to the Code View, where you can enter code for the method. Also, provide a public property UserName to hold the string that the user enters.

public string UserName { get; set; } private void PromptUserForName(object sender, EventArgs e) { Console.Write("Your name: "); UserName = Console.ReadLine(); } 10. In a similar manner drop a second activity. For Name specify

DisplayGreeting and for Execute code specify GreetUser.

11. Finally, drop a third activity. Specify PromptForExit for Name and PromptUserForExit for ExecuteCode.

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12. Implement the two additional methods.

private void GreetUser(object sender, EventArgs e) { Console.WriteLine("Hello, " + UserName); } private void PromptUserForExit(object sender, EventArgs e) { Console.WriteLine("Press Enter to exit"); Console.ReadLine(); } 13. Build and run. The program at this point is saved in

Chap05\HelloWF\Step1.

14. Examine the workflow in the Workflow Designer.

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IfElseActivity

• Typically a workflow will consist not only of sequential statements but will also contain some flow control statements.

• WF provides two activities supporting flow control:

− IfElse activity

− While activity

• See Chap05\IfElseWF for an example of an IfElse activity.

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Implementing a Branch

• To implement a branch you must specify a Condition, which can be either a Code condition or a Declarative Rule condition.

• Our example uses a Code condition, which is implemented by the method CheckLeapYear().

• Here is the code for CheckLeapYear(): private void CheckLeapYear(object sender, ConditionalEventArgs e) { e.Result = isALeapYear(Year); }

• This code uses the property Year, which is set in the ReadYear() method.

public int Year { get; set; } private void ReadYear(object sender, EventArgs e) { Console.Write("Enter year: "); Year = Convert.ToInt32(Console.ReadLine()); }

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Implementing a Branch (Cont’d)

• The second branch may or not be implemented.

• Our example implements the second branch, and both branches rely on a helper method isALeapYear().

private void CheckNotLeapYear(object sender, ConditionalEventArgs e) { e.Result = !isALeapYear(Year); } private bool isALeapYear(int year) { if (year % 400 == 0) return true; else if (year % 100 == 0) return false; else if (year % 4 == 0) return true; else return false; }

• Inside a branch is an activity, which will or will not be executed depending on the truth of the Condition.

• Here is the code for the activity inside the first branch:

private void DisplayLeapYear(object sender, EventArgs e) { Console.WriteLine("{0} is a leap year", Year); }

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While Activity

• The While activity supports looping using the normal “while” syntax.

• We’ll illustrate with an improvement of our leap year example, letting the user test multiple years in a single run of the workflow.

− See Chap05\WhileIfElseWF.

− Here is a typical run of the workflow:

Enter year (-1 to exit): 2008 2008 is a leap year Enter year (-1 to exit): 2007 2007 is not a leap year Enter year (-1 to exit): 2000 2000 is a leap year Enter year (-1 to exit): 1900 1900 is not a leap year Enter year (-1 to exit): -1 Press Enter to exit

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High-Level Workflow

• As with our earlier OrderWF example, we first show a high-level view of the workflow, with one of the nodes collapsed.

• The node that is collapse is HandleAYear, which is a Sequence activity.

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Sequence Activity

• A While node can contain only a single activity.

• At first, this may seem like a severe limitation, but one of the standard activities is a Sequence, which as the name suggests may contain multiple activities in sequence.

• In our example, the sequence consists of an IfElse activity followed by a Code activity.

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Condition in While Activity

• As with IfElse, a While activity has a Condition.

• Our example uses a Code Condition, whose method CheckForEof uses -1 as a sentinel for the end of file.

private void CheckForEof(object sender, ConditionalEventArgs e) { if (Year == -1) e.Result = false; else e.Result = true; }

• Note that a condition of true means that there will be more iterations of the loop.

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Parallel Activity

• With a Parallel activity you can schedule two or more branches to execute in parallel.

− Each branch consists of a sequence of activities.

• There is not true parallelism, because a workflow instance executes on a single thread.

• Instead, each branch will execute one activity and then surrender execution to the next branch.

− The branches are scheduled in a round-robin fashion.

• See Chap05\Parallel for a simple example.

− Here is a run of the workflow:

Sequence #1 First Sequence #2 First Sequence #3 First Sequence #1 Second Sequence #3 Second Sequence #3 Third Press Enter to exit

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Parallel Activity Workflow Diagram

• Here is a diagram showing the example workflow:

• A Parallel activity by default show two Sequences, but you can easily drop additional Sequences.

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Lab 5

Verifying Names in Hello Workflow

In this lab you will enhance the Hello Workflow program to validate names. A name is considered valid if each character in the name is a letter.

Detailed instructions are contained in the Lab 5 write-up at the end of the chapter.

Suggested time: 30 minutes

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Summary

• A workflow can be thought of as a flow of processes or tasks that produce some result.

• Windows Workflow Foundation (WF) is a framework that supports creating and running workflow applications on Windows platforms.

• You can create workflow applications using Visual Studio 2008 and the Workflow Designer.

• The units of work of a workflow are called activities. Typical activities include:

− Code

− IfElse

− While

− Sequence

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Lab 5

Verifying Names in Hello Workflow

Introduction In this lab you will enhance the Hello Workflow program to validate names. A name is considered valid if each character in the name is a letter.. Suggested Time: 30 minutes Root Directory: OIC\NewCs3 Directories: Labs\Lab5\HelloWF (do your work here) Chap05\HelloWF\Step1 (backup of starter code) Chap05\HelloWF\Step2 (answer) Instructions 1. Build and run the starter workflow.

2. Open GreetingWorkflow.cs in the WorkFlow Designer. Examine the starting workflow.

3. Drop a While activity between the PromptForName and DisplayGreeting activities. The result is shown on the next page.

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4. Provide the Name whileNameNotValidated for the While activity.

5. Specify a Code Condition with method ValidateName.

6. Implement ValidateName(). You want to set e.Result to true if there is to be another iteration of the while loop, i.e. the name is not valid. A name is considered valid if each character in the name is a letter. You can check an individual character for being a letter with the static Char.IsLetter() method. And you can convert a string to an array of characters with the ToCharArray() method. The complete code is shown on the following page.

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private void VallidateName(object sender, ConditionalEventArgs e) { bool repeat = false; foreach (char ch in UserName.ToCharArray()) { if (!Char.IsLetter(ch)) repeat = true; } e.Result = repeat; } 7. Drop a Code activity inside the While activity. Call this new Code activity

RepromptForName.

8. Note the red exclamation point icon, telling you must finish specifying the new activity. Assign the name RepromptUserForName to ExecuteCode.

9. Provide the following code for the method:

private void RepromptUserForName(object sender, EventArgs e) { Console.WriteLine("Name must be all letters"); Console.Write("Your name: "); UserName = Console.ReadLine(); } 10. Build and run. Your enhanced workflow should now be fully operational! Test with

both an invalid and a valid name.

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Your name: R2D2 Name must be all letters Your name: FriendlyRobot Hello, FriendlyRobot Press Enter to exit