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OnViewerChanged Method

Summary

Syntax

C++

protected virtual void OnViewerChanged( 
   EventArgs e 
)

  
Protected Overridable Sub OnViewerChanged( _ 
   ByVal e As EventArgs _ 
)

protected: 
virtual void OnViewerChanged(  
   EventArgs^ e 
)

Parameters

e
An System.EventArgs that contains the event data.

Remarks

Raising an event invokes the event handler through a delegate. The OnViewerChanged method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class. Notes to Inheritors: When overriding OnViewerChanged in a derived class, be sure to call the base class's OnViewerChanged method so that registered delegates receive the event.

Example

This example overrides the virtual events of the RasterImagePanViewer class.

using Leadtools.WinForms; 
using Leadtools; 
using Leadtools.Codecs; 
 
public class MyRasterImagePanViewer : RasterImagePanViewer 
{ 
   //. 
   //. 
   //. 
   protected override void OnViewerChanged(EventArgs e) 
   { 
      base.OnViewerChanged(e); 
 
      Console.WriteLine("OnViewerChanged is called"); 
   } 
 
   protected override void OnRectangleColorChanged(EventArgs e) 
   { 
      base.OnRectangleColorChanged(e); 
 
      Console.WriteLine("OnRectangleColorChanged is called"); 
   } 
 
   protected override void OnImageColorChanged(EventArgs e) 
   { 
      base.OnImageColorChanged(e); 
 
      Console.WriteLine("OnImageColorChanged is called"); 
   } 
 
   protected override void OnClipCursorChanged(EventArgs e) 
   { 
      base.OnClipCursorChanged(e); 
 
      Console.WriteLine("OnClipCursorChanged is called"); 
   } 
 
   protected override void OnPaint(PaintEventArgs e) 
   { 
      base.OnPaint(e); 
 
      Console.WriteLine("OnPaint is called"); 
   } 
 
   protected override void OnMouseDown(MouseEventArgs e) 
   { 
      base.OnMouseDown(e); 
 
      Console.WriteLine("OnMouseDown is called"); 
   } 
 
   protected override void OnMouseMove(MouseEventArgs e) 
   { 
      base.OnMouseMove(e); 
 
      Console.WriteLine("OnMouseMove is called"); 
   } 
 
   protected override void OnMouseUp(MouseEventArgs e) 
   { 
      base.OnMouseUp(e); 
 
      Console.WriteLine("OnMouseUp is called"); 
   } 
 
   protected override void OnLostFocus(EventArgs e) 
   { 
      base.OnLostFocus(e); 
 
      Console.WriteLine("OnLostFocus is called"); 
   } 
 
   protected override void OnSizeChanged(EventArgs e) 
   { 
      base.OnSizeChanged(e); 
 
      Console.WriteLine("OnSizeChanged is called"); 
   } 
}

Imports Leadtools.WinForms 
Imports Leadtools 
Imports Leadtools.Codecs 
 
Public Class MyRasterImagePanViewer 
   Inherits RasterImagePanViewer 
   '. 
   '. 
   '. 
   Protected Overrides Sub OnViewerChanged(ByVal e As EventArgs) 
      MyBase.OnViewerChanged(e) 
 
      Console.WriteLine("OnViewerChanged is called") 
   End Sub 
 
   Protected Overrides Sub OnRectangleColorChanged(ByVal e As EventArgs) 
      MyBase.OnRectangleColorChanged(e) 
 
      Console.WriteLine("OnRectangleColorChanged is called") 
   End Sub 
 
   Protected Overrides Sub OnImageColorChanged(ByVal e As EventArgs) 
      MyBase.OnImageColorChanged(e) 
 
      Console.WriteLine("OnImageColorChanged is called") 
   End Sub 
 
   Protected Overrides Sub OnClipCursorChanged(ByVal e As EventArgs) 
      MyBase.OnClipCursorChanged(e) 
 
      Console.WriteLine("OnClipCursorChanged is called") 
   End Sub 
 
   Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs) 
      MyBase.OnPaint(e) 
 
      Console.WriteLine("OnPaint is called") 
   End Sub 
 
   Protected Overrides Sub OnMouseDown(ByVal e As MouseEventArgs) 
      MyBase.OnMouseDown(e) 
 
      Console.WriteLine("OnMouseDown is called") 
   End Sub 
 
   Protected Overrides Sub OnMouseMove(ByVal e As MouseEventArgs) 
      MyBase.OnMouseMove(e) 
 
      Console.WriteLine("OnMouseMove is called") 
   End Sub 
 
   Protected Overrides Sub OnMouseUp(ByVal e As MouseEventArgs) 
      MyBase.OnMouseUp(e) 
 
      Console.WriteLine("OnMouseUp is called") 
   End Sub 
 
   Protected Overrides Sub OnLostFocus(ByVal e As EventArgs) 
      MyBase.OnLostFocus(e) 
 
      Console.WriteLine("OnLostFocus is called") 
   End Sub 
 
   Protected Overrides Sub OnSizeChanged(ByVal e As EventArgs) 
      MyBase.OnSizeChanged(e) 
 
      Console.WriteLine("OnSizeChanged is called") 
   End Sub 
End Class

Requirements

Target Platforms

Reference

RasterImagePanViewer Class

RasterImagePanViewer Members

Help Version 19.0.2017.10.27

Leadtools.WinForms Assembly

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Leadtools.WinForms Namespace

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