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Changed Event
See Also 
Leadtools Namespace > RasterImage Class : Changed Event



Occurs when the image data or attributes has changed. Supported in Silverlight, Windows Phone 7

Syntax

Visual Basic (Declaration) 
Public Event Changed As EventHandler(Of RasterImageChangedEventArgs)
Visual Basic (Usage)Copy Code
Dim instance As RasterImage
Dim handler As EventHandler(Of RasterImageChangedEventArgs)
 
AddHandler instance.Changed, handler
C++/CLI 
public:
event EventHandler<RasterImageChangedEventArgs^>^ Changed

Event Data

The event handler receives an argument of type RasterImageChangedEventArgs containing data related to this event. The following RasterImageChangedEventArgs properties provide information specific to this event.

PropertyDescription
Flags Gets the flags for the RasterImage.Changed event. Supported in Silverlight, Windows Phone 7

Example

Visual BasicCopy Code
Public Sub ChangedExample()
      Dim codecs As RasterCodecs = New RasterCodecs()

      Dim srcFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp")

      ' Load the image
      Dim img As RasterImage = codecs.Load(srcFileName)

      ' Subscribe to the Changed event of this image
      AddHandler img.Changed, AddressOf img_Changed

      ' Call a few methods and image processing commands that changes the image
      Console.WriteLine("Calling FlipViewPerspective")
      img.FlipViewPerspective(True)

      Console.WriteLine("Calling RotateViewPerspective")
      img.RotateViewPerspective(90)

      Console.WriteLine("Calling FlipCommand")
      Dim flip As FlipCommand = New FlipCommand(True)
      flip.Run(img)

      ' Now disable firing the events and call the methods again
      Console.WriteLine("Disabling the events")
      img.DisableEvents()

      Console.WriteLine("Calling FlipViewPerspective")
      img.FlipViewPerspective(True)

      Console.WriteLine("Calling RotateViewPerspective")
      img.RotateViewPerspective(90)

      Console.WriteLine("Calling FlipCommand while")
      flip.Run(img)

      ' Re-enable the events and fire it manually
      Console.WriteLine("Re-enabling the events")
      img.EnableEvents()

      Console.WriteLine("Firing the event manually")
      Dim flags As RasterImageChangedFlags = RasterImageChangedFlags.Data Or RasterImageChangedFlags.ViewPerspective
      Dim e As RasterImageChangedEventArgs = New RasterImageChangedEventArgs(flags)

      img.OnChanged(e)

      ' Clean up
      RemoveHandler img.Changed, AddressOf img_Changed
      img.Dispose()
      codecs.Dispose()
   End Sub

   Private Sub img_Changed(ByVal sender As Object, ByVal e As RasterImageChangedEventArgs)
      ' Show the changed flags
      Console.WriteLine("Changed: {0}", e.Flags)
   End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class
C#Copy Code
public void ChangedExample()
   {
      RasterCodecs codecs = new RasterCodecs();

      string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp");

      // Load the image
      RasterImage img = codecs.Load(srcFileName);

      // Subscribe to the Changed event of this image
      img.Changed += new EventHandler<RasterImageChangedEventArgs>(img_Changed);

      // Call a few methods and image processing commands that changes the image
      Console.WriteLine("Calling FlipViewPerspective");
      img.FlipViewPerspective(true);

      Console.WriteLine("Calling RotateViewPerspective");
      img.RotateViewPerspective(90);

      Console.WriteLine("Calling FlipCommand");
      FlipCommand flip = new FlipCommand(true);
      flip.Run(img);

      // Now disable firing the events and call the methods again
      Console.WriteLine("Disabling the events");
      img.DisableEvents();

      Console.WriteLine("Calling FlipViewPerspective");
      img.FlipViewPerspective(true);

      Console.WriteLine("Calling RotateViewPerspective");
      img.RotateViewPerspective(90);

      Console.WriteLine("Calling FlipCommand while");
      flip.Run(img);

      // Re-enable the events and fire it manually
      Console.WriteLine("Re-enabling the events");
      img.EnableEvents();

      Console.WriteLine("Firing the event manually");
      RasterImageChangedFlags flags = RasterImageChangedFlags.Data | RasterImageChangedFlags.ViewPerspective;
      RasterImageChangedEventArgs e = new RasterImageChangedEventArgs(flags);

      img.OnChanged(e);

      // Clean up
      img.Changed -= new EventHandler<RasterImageChangedEventArgs>(img_Changed);
      img.Dispose();
      codecs.Dispose();
   }

   void img_Changed(object sender, RasterImageChangedEventArgs e)
   {
      // Show the changed flags
      Console.WriteLine("Changed: {0}", e.Flags);
   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}
SilverlightCSharpCopy Code
public void ChangedExample()
{
   // create a new image to work with
   RasterImage img = new RasterImage(RasterMemoryFlags.Conventional, 500, 500, 24, RasterByteOrder.Bgr, RasterViewPerspective.TopLeft, null, null, 0);
   // Subscribe to the Changed event of this image
   img.Changed += new EventHandler<RasterImageChangedEventArgs>(img_Changed);

   // Call a few methods and image processing commands that changes the image
   Debug.WriteLine("Calling FlipViewPerspective");
   img.FlipViewPerspective(true);

   Debug.WriteLine("Calling RotateViewPerspective");
   img.RotateViewPerspective(90);

   Debug.WriteLine("Calling FlipCommand");
   FlipCommand flip = new FlipCommand(true);
   flip.Run(img);

   // Now disable firing the events and call the methods again
   Debug.WriteLine("Disabling the events");
   img.DisableEvents();

   Debug.WriteLine("Calling FlipViewPerspective");
   img.FlipViewPerspective(true);

   Debug.WriteLine("Calling RotateViewPerspective");
   img.RotateViewPerspective(90);

   Debug.WriteLine("Calling FlipCommand while");
   flip.Run(img);

   // Re-enable the events and fire it manually
   Debug.WriteLine("Re-enabling the events");
   img.EnableEvents();

   Debug.WriteLine("Firing the event manually");
   RasterImageChangedFlags flags = RasterImageChangedFlags.Data | RasterImageChangedFlags.ViewPerspective;
   RasterImageChangedEventArgs e = new RasterImageChangedEventArgs(flags);

   img.OnChanged(e);

   // Clean up
   img.Changed -= new EventHandler<RasterImageChangedEventArgs>(img_Changed);
   img.Dispose();
}

void img_Changed(object sender, RasterImageChangedEventArgs e)
{
   // Show the changed flags
   Debug.WriteLine("Changed: {0}", e.Flags);
}
SilverlightVBCopy Code
Public Sub ChangedExample()
   ' create a new image to work with
   Dim img As RasterImage = New RasterImage(RasterMemoryFlags.Conventional, 500, 500, 24, RasterByteOrder.Bgr, RasterViewPerspective.TopLeft, Nothing, Nothing, 0)
   ' Subscribe to the Changed event of this image
   AddHandler img.Changed, AddressOf img_Changed

   ' Call a few methods and image processing commands that changes the image
   Debug.WriteLine("Calling FlipViewPerspective")
   img.FlipViewPerspective(True)

   Debug.WriteLine("Calling RotateViewPerspective")
   img.RotateViewPerspective(90)

   Debug.WriteLine("Calling FlipCommand")
   Dim flip As FlipCommand = New FlipCommand(True)
   flip.Run(img)

   ' Now disable firing the events and call the methods again
   Debug.WriteLine("Disabling the events")
   img.DisableEvents()

   Debug.WriteLine("Calling FlipViewPerspective")
   img.FlipViewPerspective(True)

   Debug.WriteLine("Calling RotateViewPerspective")
   img.RotateViewPerspective(90)

   Debug.WriteLine("Calling FlipCommand while")
   flip.Run(img)

   ' Re-enable the events and fire it manually
   Debug.WriteLine("Re-enabling the events")
   img.EnableEvents()

   Debug.WriteLine("Firing the event manually")
   Dim flags As RasterImageChangedFlags = RasterImageChangedFlags.Data Or RasterImageChangedFlags.ViewPerspective
   Dim e As RasterImageChangedEventArgs = New RasterImageChangedEventArgs(flags)

   img.OnChanged(e)

   ' Clean up
   RemoveHandler img.Changed, AddressOf img_Changed
   img.Dispose()
End Sub

Private Sub img_Changed(ByVal sender As Object, ByVal e As RasterImageChangedEventArgs)
   ' Show the changed flags
   Debug.WriteLine("Changed: {0}", e.Flags)
End Sub

Remarks

When the data or attributes of a RasterImage object changes, the RasterImage.Changed event is fired with information of what has changed. For example, you can subscribe to this event to get notified when the RasterImage object has been changed and need to be updated in your user interface by re-painting it.

For more information, refer to RasterImageChangedEventArgs.

Requirements

Target Platforms: Silverlight, Windows XP, Windows Server 2003 family, Windows Server 2008 family, Windows Vista, Windows 7, MAC OS/X (Intel Only), Windows Phone 7

See Also