Debugging and Menus

Part07dbg --- Solving the problem, Debugging in Break time, Menus

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Carefully Plan the Solution

• Understand the inputs and outputs of desired solution.

• Draw a sketch of proposed solution showing placement of controls.

• Assign meaningful names to controls using CSR naming conventions.

• Decide what variables will be required.• Choose test data and do hand/calculator

calculations so that you know what answers should be produced by the program.

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3 Modes of Operation

• Design Time --- before application is run• Run Time --- when application is running• Break Time --- when run time is suspended, for

the purpose of debugging

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Design Time

• Add controls to form via Designer.• Set/review Property values for controls via

Property Window.• Add code to “handle” various events and

set/change Property values (at runtime) via Code Window.

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Run Time

• Code executed in event handler functions can– change Property values for controls (Visible,

ForeColor, BackColor, Text).– run methods to reset Focus(), Clear() contents, write

variable/control values to the Output Window (via Debug.Writeline()) etc.

– perform calculations/comparisons of variable values. – display variable values in controls. – handle various events.

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How to Debug Code without using Break Time

• Trace through your program by hand, recording variable values (desk-checking).

• Insert statements into code that will print messages and/or control or variable values to the Output Window, so you can follow the progress through your code and see variable values, without preparing values for output in controls. System.Diagnostics.Debug.WriteLine(totRed); //print value of variable ---or---using System.Diagnostics; //add at top of programDebug.WriteLine(lblTotalBlue.Text); //print value of control

Using Visual Studio.NET Debugging Capabilities

Using Break Time

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Setting Break Points

• To set a breakpoint in your code, which will suspend execution before designated statement, – click in the light gray border to the left of the line of

code.– press F9.

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Helpful Windows during Break Time

• Code Window– Hover mouse over variable/control name to display its

value.

• Locals Window– View values of local variables.– Class-level variables values can be viewed by clicking

the + in front of this.

• Autos Window– Values of all variables in use near the highlighted line.

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Stepping through Code

• Continue --- continue running (till next breakpoint)

• Step Into --- execute 1 statement• Step Over --- execute 1 statement but

don’t branch into any called method• Step Out --- advance rapidly until reach

end of function/method, then back to 1 statement at a time execution

• Restart --- start back at the beginning• Stop Debugging

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Removing Breakpoints

• To clear one breakpoint, position cursor and – click in gray border to left of designated line of code.– press F9.– choose Debug, Toggle Breakpoint from menu.

• To clear several breakpoints, choose Debug, Delete All Breakpoints from menu.

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Let’s Try Debugging Together

• Get the Ch04DebugCSR 2005 project folder from Dee Gudmundsen CIS205 on drive z:

• A zipped file, Ch04DebugCSR.zip, containing this project folder is also posted on my website in the in part07.zip of the Demonstration files section.

• This problem has error(s), which we will discover using the Debugging facilities of Visual Studio.NET.

Introduction to Menus

MenuStrip and ContextMenuStrip

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The MenuStrip Control

• The MenuStrip control can be used to add a menu to the top of a form.

• The MenuStrip control is new in VS.NET 2005. It replaces the MainMenu component in earlier versions of VS.NET.

• MainMenu components did not occupy the client area of the form. The client area of a form is the size of the form, minus the nonclient elements such as scroll bars, borders, and title bars.

• MenuStrip controls do occupy the client area of the form.

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The Client Area

• The client area, defined by the ClientSize object and its Height and Width properties is that part of the form that can host controls.

ClientSize.Width

ClientSize.Height

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MainMenu

• The icon for a MenuStrip control resides in the component tray area of the Designer.

• The MenuStrip control supports a point and click editor for constructing a menu with MenuItems.

• MenuItems are essentially buttons that are contained in the Items collection associated with the MenuStrip control.

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MenuItems

• MenuItems are added to a MenuStrip by typing the Text property of a MenuItem in a position suggested by the menu editor.

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Renaming Menu Items

• MenuItems are controls and should be given meaningful names.

• A good organizational strategy is to use a compound name consisting of the menu (top line) name and the MenuItem name.

• Use the prefix mnu for MenuItems.

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Coding Handlers for MenuItems

• The Click event is the default event for MenuItems and their handler functions may be created using the same techniques as with Buttons.

• We will add code to our MenuItem Click handler functions to assign different values to the BackColor property of the form.

SimpleMenu

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Adding Menu Hot Keys

• Hot keys allow users to open menus and select menu items using the keyboard.

• Menus are opened by pressing Alt and the appropriate hot key.

• MenuItems are selected by simply pressing the hot key.

• Hot keys are created by inserting an & character ahead of the character (that will act as a hot key) in the Text property of a MenuItem.

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Hot Keys at Run Time

• Hot keys appear underlined at run time.• Hot keys in menus appear when the Alt key is

pressed.• Hot keys in open menus (MenuItems) appear

automatically.

HotKeys

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Menu Shortcuts

• Shortcuts allow selection of a menu item without even opening a menu.

• Shortcuts are assigned to function keys or control key combinations (e.g. ctrl + C).

• Shortcuts are applied to MenuItems by assigning a value to the Shortcut property of the MenuItem.

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Menu Shortcuts

• An additional MenuItem property, ShowShortcuts, sets whether the shortcut will appear on the menu at run time.

• Curiously, shortcuts are never visible at design time.

capture of shortcuts at run time ShortCuts

InvisibleShortCuts

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Menu Branching

• Branched menus are easily created by typing new MenuItem Text properties in the indicated positions.

• Naming conventions should recognize the node at which the menu branches.

BranchedMenu

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Menu Separators

• Menu separators appear as simple horizontal lines to arrange menu items into groups.

• They are created by simply typing a hyphen for the Text Property of a MenuItem or right-clicking and choose Insert Separator.

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ContextMenuStrips

• Rather than appear at the top of a form, ContextMenuStrips “pop up” when an object is right-clicked.

• Choose the ContextMenuStrip control from the Toolbox. Edit in the same way as a MenuStrip.

• Use cmu as the prefix for Context MenuItems• Associate the ContextMenuStrip with a control

by setting the ContextMenuStrip property of the control. ContextMenus

ContextMenusDBG

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Alternate Main Menus

• Multiple MenuStrip controls may be added to a form.

• To switch among the MenuStrips available:1. assign the desired MenuStrip name to the

MainMenuStrip property of the form.

2. set the Visible property of desired MenuStrip to true and the Visible property of undesired MenuStrip to false.

AlternateMainMenus

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Let’s Do a Problem Together

• Make a copy of ch4ex4_6pg180 complete and paste it to your hard drive.

• We will add menus to this existing problem; see ex 5.1 pg 217 for new menu layout for this revised problem.

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Writing functions/methods

• So far the only functions/methods we have been working with are methods that handle events; the skeleton of these functions were typed for us when we double-click a control.

• You will recall from C++, that it is often convenient to write our own functions:– To break a problem into smaller parts– Because some code will be executed in more than 1

place (reusable code)

• We will want to write our own functions in C#, as well, but let’s review C++ functions syntax.

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C++ Functions

• Functions consist of:– Function prototype --- declares the function, specifies

data type of returned value, lists number of parameters and their data types

– Function definition --- function header (copy of prototype without ;) plus actual code to be executed

• These could be written within the source program file or contained in separate .cpp and .h files; (#include statement was necessary to incorporate these files).

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C++ Function Syntax

Syntax:return-type functionName(data-type variable1, data-type variable2, …)

Example 1://function prototypedouble calcInterest (int y, double p, double r);

//function definitiondouble calcInterest(int y, double p, double r){ double temp; temp = p * r * y; return temp;}

//function call in main()interest = calcInterest (years, principal, rate);

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Another C++ Function Example

Syntax:return-type functionName(data-type variable1, data-type variable2, …)

Example2://function prototypevoid printLoanInfo(int y, double p, double r, double i);

//function definitionvoid printLoanInfo(int y, double p, double r, double i){ cout << “You will have to pay $“ << i <<

<< “ interest on your loan of $“ << p << “ for a term of “ << y << “ years at a rate of “ << r << “%.\n”;

}

//function call in main()printLoanInfo(years, principal, rate, interest);

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C# Function/Method Syntax

Syntax:

private return-type functionName(data-type variable1, data-type variable2, …)

Example 1://function definition

private decimal calcInterest(int y, decimal p, decimal r)

{

decimal temp;

temp = p * r * y;

return temp;

}

//function call

interest = calcInterest(years, principal, rate);

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Functions: C++ vs. C#

• C# functions will generally have the keyword private as access modifier. – private indicates this function can only be used within

this class (form) – public indicates this function can be used within other

classes

• No function prototype or #includes are required; just the function definition (without ;) is required.

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Let’s Do a Problem Together

• Let’s plan the solution to ch5ex5.2pg217