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Ray KonopkaRay Konopka
Creating Custom Microsoft .NET Framework
Controls in Delphi
Creating Custom Microsoft .NET Framework
Controls in Delphi
2
AgendaAgenda
.NET Component Model
Comparing the FCL to the VCL
Custom Events
Custom Painting
Component Related Attributes
Sample Control
.NET Component Model
Comparing the FCL to the VCL
Custom Events
Custom Painting
Component Related Attributes
Sample Control
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.NET Component Model.NET Component Model
Defined in the System.ComponentModel namespace
Includes System.ComponentModel.Component
declaration Common Delegates Component Related Attribute declarations Licensing Classes Design-time Support Classes
Defined in the System.ComponentModel namespace
Includes System.ComponentModel.Component
declaration Common Delegates Component Related Attribute declarations Licensing Classes Design-time Support Classes
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Component ClassComponent Class
System.ComponentModel.Component provides the base implementation of IComponent in the FCL
Defines the following properties DesignMode Container Site Events
Descend from System.ComponentModel.Component to create a nonvisual component
System.ComponentModel.Component provides the base implementation of IComponent in the FCL
Defines the following properties DesignMode Container Site Events
Descend from System.ComponentModel.Component to create a nonvisual component
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Two Control Classes in .NETTwo Control Classes in .NET
Most visual controls in .NET will descend from one of two classes:
System.Windows.Forms.Control Base WinForms Control class Most similar to existing component models (e.g.
VCL) Rendering handled through Graphics class (i.e.
GDI+)
System.Web.UI.Control Base ASP.NET Server Control class Renders markup text used by a client’s browser
or viewing device to display visual elements.
Most visual controls in .NET will descend from one of two classes:
System.Windows.Forms.Control Base WinForms Control class Most similar to existing component models (e.g.
VCL) Rendering handled through Graphics class (i.e.
GDI+)
System.Web.UI.Control Base ASP.NET Server Control class Renders markup text used by a client’s browser
or viewing device to display visual elements.
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System.Windows.Forms.Control
System.Windows.Forms.Control
Implements basic functionality for visualizationDefines the control’s bounds (i.e. its Position
and Size)Provides a window handle (Handle)Provides access to keyboard eventsProvides access to mouse eventsProvides access to paint eventsSupports ambient properties
Cursor, Font, BackColor, ForeColor, RightToLeft.
Implements basic functionality for visualizationDefines the control’s bounds (i.e. its Position
and Size)Provides a window handle (Handle)Provides access to keyboard eventsProvides access to mouse eventsProvides access to paint eventsSupports ambient properties
Cursor, Font, BackColor, ForeColor, RightToLeft.
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Comparing the FCL to the VCL
Comparing the FCL to the VCL
FCL is quite similar to the VCL, but there are significant differences
No equivalent to TGraphicControl
Actually, no TWinControl or TCustomControl classes either
System.Windows.Forms.Control is more like TCustomControl than TControl
Significantly fewer TCustomXxxx class called XxxxBase in FCL
FCL is quite similar to the VCL, but there are significant differences
No equivalent to TGraphicControl
Actually, no TWinControl or TCustomControl classes either
System.Windows.Forms.Control is more like TCustomControl than TControl
Significantly fewer TCustomXxxx class called XxxxBase in FCL
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Where is the Align property?
Where is the Align property?
Most of the functionality implemented in the VCL base classes is available in the base FCL classes
However, there are many property name changes Align Dock Caption Text Color BackColor Font.Color ForeColor PopupMenu ContextMenu ModalResult DialogResult etc.
Tag is an Object
ParentXxxx properties replaced with ambient properties
Most of the functionality implemented in the VCL base classes is available in the base FCL classes
However, there are many property name changes Align Dock Caption Text Color BackColor Font.Color ForeColor PopupMenu ContextMenu ModalResult DialogResult etc.
Tag is an Object
ParentXxxx properties replaced with ambient properties
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Control StylesControl Styles
TControl.ControlStyle replaced with GetStyle/SetStyle method pair
Some, but not all, styles have corresponding public properties ResizeRedraw
TControl.ControlStyle replaced with GetStyle/SetStyle method pair
Some, but not all, styles have corresponding public properties ResizeRedraw
SetStyle( ControlStyles.ResizeRedraw, True );SetStyle( ControlStyles.Opaque, True );
// Double BufferingSetStyle( ControlStyles.UserPaint, True );SetStyle( ControlStyles.AllPaintingInWmPaint, True );SetStyle( ControlStyles.DoubleBuffer, True );
SetStyle( ControlStyles.ResizeRedraw, True );SetStyle( ControlStyles.Opaque, True );
// Double BufferingSetStyle( ControlStyles.UserPaint, True );SetStyle( ControlStyles.AllPaintingInWmPaint, True );SetStyle( ControlStyles.DoubleBuffer, True );
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Component NotificationsComponent Notifications
Component notifications allow descendants to react to state changes implemented in an ancestor class
In the VCL, a component responds to notifications by handling special messages e.g. cm_EnabledChanged
In .NET, a component responds to notifications by overriding a method OnEnabledChanged Event Dispatch Method
.NET even surfaces component notifications as public events EnabledChanged Event
Component notifications allow descendants to react to state changes implemented in an ancestor class
In the VCL, a component responds to notifications by handling special messages e.g. cm_EnabledChanged
In .NET, a component responds to notifications by overriding a method OnEnabledChanged Event Dispatch Method
.NET even surfaces component notifications as public events EnabledChanged Event
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FCL and VCL EventsFCL and VCL Events
Unfortunately, the naming convention used for events in the FCL is opposite that used in the VCL
In the VCL… OnPaint is the event Paint is the event dispatch method
In the FCL… OnPaint is the event dispatch method Paint is the event
Unfortunately, the naming convention used for events in the FCL is opposite that used in the VCL
In the VCL… OnPaint is the event Paint is the event dispatch method
In the FCL… OnPaint is the event dispatch method Paint is the event
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FCL and VCL EventsFCL and VCL Events
Please Note: Unfortunately, it is common in .NET literature to
see statements like“…take a look at the OnPaint event handler…”
Problem is that base (ancestor) does not get called and thus the real event never gets raised
Please Note: Unfortunately, it is common in .NET literature to
see statements like“…take a look at the OnPaint event handler…”
Problem is that base (ancestor) does not get called and thus the real event never gets raised
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EventsEvents
Events allow customization through delegation
Events are properties
Implemented using Delegates
Events are optional
Events allow customization through delegation
Events are properties
Implemented using Delegates
Events are optional
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Creating a Custom EventCreating a Custom Event
Determine the action that triggers event
Define the event type (i.e. the Delegate) Specifies the parameters that will be sent to an
event handler
Declare the event property Singleton Event (read/write) Multicast Event (add/remove)
Dispatch the event when it occurs.
Determine the action that triggers event
Define the event type (i.e. the Delegate) Specifies the parameters that will be sent to an
event handler
Declare the event property Singleton Event (read/write) Multicast Event (add/remove)
Dispatch the event when it occurs.
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Determine Event TriggerDetermine Event Trigger
Events allow developers to “hook” into normal processing
Example Generate a ValueChanged event when data
represented by the component changes
Events allow developers to “hook” into normal processing
Example Generate a ValueChanged event when data
represented by the component changes
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DelegatesDelegates
The FCL utilizes Delegates to support events
A delegate is a class that encapsulates a linked-list of method pointers
With delegates an event can be sent to multiple subscribers
Specify the parameters that will be sent to event handlers.
The FCL utilizes Delegates to support events
A delegate is a class that encapsulates a linked-list of method pointers
With delegates an event can be sent to multiple subscribers
Specify the parameters that will be sent to event handlers.
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Define the DelegateDefine the Delegate
May be possible to use predefined delegate e.g. EventHandler
First parameter always “object sender”
Second parameter always EventArgs or descendant
If you require passing additional parameters, you’ll need to create a new EventArgs descendant
May be possible to use predefined delegate e.g. EventHandler
First parameter always “object sender”
Second parameter always EventArgs or descendant
If you require passing additional parameters, you’ll need to create a new EventArgs descendantValueChangingEventHandler =
procedure ( sender: System.Object; e: ValueChangingEventArgs ) of object;
ValueChangingEventHandler = procedure ( sender: System.Object; e: ValueChangingEventArgs ) of object;
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Declare the Event PropertyDeclare the Event Property
Unlike the VCL, by convention event names in the FCL do not start with “On”
Unlike the VCL, by convention event names in the FCL do not start with “On”
// Multicast Eventproperty ValueChanged: EventHandler add FValueChanged remove FValueChanged;
// Singleton Eventproperty ValueChanging: ValueChangingEventHandler read FValueChanging write FValueChanging;
// Multicast Eventproperty ValueChanged: EventHandler add FValueChanged remove FValueChanged;
// Singleton Eventproperty ValueChanging: ValueChangingEventHandler read FValueChanging write FValueChanging;
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Raise the EventRaise the Event
Use an Event Dispatch Method
In FCL, event dispatch methods start with “On”
Usually defined as strict protected and virtual
Calling the event (e.g. FValueChanged) causes all of the event handlers in the delegate’s list to be called
Use an Event Dispatch Method
In FCL, event dispatch methods start with “On”
Usually defined as strict protected and virtual
Calling the event (e.g. FValueChanged) causes all of the event handlers in the delegate’s list to be called
procedure RkSpinner.OnValueChanged( E: EventArgs );begin if Assigned( FValueChanged ) then FValueChanged( Self, E );end;
procedure RkSpinner.OnValueChanged( E: EventArgs );begin if Assigned( FValueChanged ) then FValueChanged( Self, E );end;
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Custom PaintingCustom Painting
Custom painting is supported by Graphics class (i.e. GDI+) System.Drawing System.Drawing.Drawing2D System.Drawing.Imaging System.Drawing.Text
GDI+ Features Alpha Blending & Anti-Aliased 2D Drawing Gradient Brushes Universal Transformations & Floating Point
coordinates Support for more Image formats
BMP, GIF, JPEG, PNG, TIFF, ICON, WMF, EMF.
Custom painting is supported by Graphics class (i.e. GDI+) System.Drawing System.Drawing.Drawing2D System.Drawing.Imaging System.Drawing.Text
GDI+ Features Alpha Blending & Anti-Aliased 2D Drawing Gradient Brushes Universal Transformations & Floating Point
coordinates Support for more Image formats
BMP, GIF, JPEG, PNG, TIFF, ICON, WMF, EMF.
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GDI+ Programming ModelGDI+ Programming Model
No more device contexts (DC) – Graphics Object
GDI+ is Stateless No more selecting pens and brushes into a DC Pens, Brushes, etc. are passed to each GDI+
drawing method
Graphic elements are no longer drawn with both Pen and Brush Draw methods use a Pen (eg. DrawRectangle) Fill methods use a Brush (eg. FillEllipse).
No more device contexts (DC) – Graphics Object
GDI+ is Stateless No more selecting pens and brushes into a DC Pens, Brushes, etc. are passed to each GDI+
drawing method
Graphic elements are no longer drawn with both Pen and Brush Draw methods use a Pen (eg. DrawRectangle) Fill methods use a Brush (eg. FillEllipse).
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GDI+ Programming ModelGDI+ Programming Model
Colors support Alpha Channels ARGB format
0x880000FF semi-transparent blue
A = 0x00 fully transparent A = 0xFF fully opaque
Rectangles, Points, etc. are classes r.Inflate( 5, 5 ); // Instead of InflateRect( r, 5,
5 );
Rectangles are defined differently! Left, Top, Width, Height.
Colors support Alpha Channels ARGB format
0x880000FF semi-transparent blue
A = 0x00 fully transparent A = 0xFF fully opaque
Rectangles, Points, etc. are classes r.Inflate( 5, 5 ); // Instead of InflateRect( r, 5,
5 );
Rectangles are defined differently! Left, Top, Width, Height.
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GDI+ Programming ModelGDI+ Programming Model
Obtaining a Graphics Object Passed to OnPaint methods in
PaintEventArgs Request one using
Graphics.FromHwnd( Handle ) If utilizing double-buffering, do not use
FromHwnd
Cleaning Up Dispose all GDI+ objects Dispose Graphics object if requested via
FromHwnd
Obtaining a Graphics Object Passed to OnPaint methods in
PaintEventArgs Request one using
Graphics.FromHwnd( Handle ) If utilizing double-buffering, do not use
FromHwnd
Cleaning Up Dispose all GDI+ objects Dispose Graphics object if requested via
FromHwnd
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AttributesAttributes
Attributes used to modify the behavior of properties, methods, events
Attributes used to modify the behavior of properties, methods, events
[ Category( 'Appearance' ), Description( 'The width of buttons, in pixels.' ), DefaultValue( 18 ) ]
property ButtonWidth: Integer read FButtonWidth write SetButtonWidth;
[ Category( 'Appearance' ), Description( 'The width of buttons, in pixels.' ), DefaultValue( 18 ) ]
property ButtonWidth: Integer read FButtonWidth write SetButtonWidth;
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AttributesAttributes
Category
Description
Browsable
DefaultValue
DefaultProperty & DefaultEvent
Localizable
ToolboxBitmap
Category
Description
Browsable
DefaultValue
DefaultProperty & DefaultEvent
Localizable
ToolboxBitmap
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ExampleExample
RayKonopka.Delphi.Controls Assembly RkSpinner Component
RayKonopka.Delphi.Controls Assembly RkSpinner Component
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ReferencesReferences
Microsoft Development Network (MSDN) Design Guidelines for Class Library Developers Developing Components Developing Windows Forms Controls
Applied .NET Framework Development Jeffrey Richter
Programming Microsoft .NET Jeff Prosise
Microsoft Development Network (MSDN) Design Guidelines for Class Library Developers Developing Components Developing Windows Forms Controls
Applied .NET Framework Development Jeffrey Richter
Programming Microsoft .NET Jeff Prosise
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The Finish LineThe Finish Line
Contact Information
Evaluation Forms
Questions & Answers
Contact Information
Evaluation Forms
Questions & Answers
Ray [email protected]://www.raize.com
Ray [email protected]://www.raize.com
