TransformChanged Event (ImageViewer)

Occurs when any visual transformation properties changes in the control.

Syntax

Visual Basic
C#
WinRT C#
WinRT JavaScript
C++

public event EventHandler TransformChanged

'Declaration
 
Public Event TransformChanged As EventHandler

'Usage
 
Dim instance As ImageViewer
Dim handler As EventHandler
 
AddHandler instance.TransformChanged, handler

public event EventHandler TransformChanged

add_TransformChanged(function(sender, e))
remove_TransformChanged(function(sender, e))

public:
event EventHandler^ TransformChanged

This event is raised if any of the properties of the controls that effects the way the image will be displayed is changed such as:

The control size
The image physical size in pixels and if using the image resolution is enabled with the UseDpi property
Any manual correction with the AspectRatioCorrection
The current zoom using the ScaleFactor property
The current display and automatic adjustment set with the SizeMode property
Image viewing transformation using the Flip, Reverse and RotateAngle properties

You can use the TransformChanged event as catch all placeholder to update external properties or UI elements whenever the user scrolls or zooms the image for example instead of hooking to individual properties OnXYZChanged events.

Visual Basic
C#
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Copy Code

Private Sub viewer_TransformChanged(ByVal sender As Object, ByVal e As EventArgs)
    Dim viewer As ImageViewer = TryCast(sender, ImageViewer)
    Dim s As String = String.Format("TransformChanged Event: {0}", viewer.Transform.ToString())
    MessageBox.Show(s)
End Sub
Public Sub ImageViewer_TransformChanged(ByVal viewer As ImageViewer)
    AddHandler viewer.TransformChanged, AddressOf viewer_TransformChanged

    Select Case viewer.SizeMode
        Case SizeMode.Fit
            viewer.SizeMode = SizeMode.FitAlways

        Case SizeMode.FitAlways
            viewer.SizeMode = SizeMode.FitWidth

        Case SizeMode.FitWidth
            viewer.SizeMode = SizeMode.Normal

        Case SizeMode.Normal
            viewer.SizeMode = SizeMode.Stretch

        Case SizeMode.Stretch
            viewer.SizeMode = SizeMode.Fit
    End Select

    RemoveHandler viewer.TransformChanged, AddressOf viewer_TransformChanged
End Sub

private void viewer_TransformChanged(object sender, EventArgs e)
{
   ImageViewer viewer = sender as ImageViewer;
   string s = string.Format("TransformChanged Event: {0}", viewer.Transform.ToString());
   MessageBox.Show(s);
}
public void ImageViewer_TransformChanged(ImageViewer viewer)
{
   viewer.TransformChanged += new EventHandler(viewer_TransformChanged);

   switch (viewer.SizeMode)
   {
      case SizeMode.Fit:
         viewer.SizeMode = SizeMode.FitAlways;
         break;

      case SizeMode.FitAlways:
         viewer.SizeMode = SizeMode.FitWidth;
         break;

      case SizeMode.FitWidth:
         viewer.SizeMode = SizeMode.Normal;
         break;

      case SizeMode.Normal:
         viewer.SizeMode = SizeMode.Stretch;
         break;

      case SizeMode.Stretch:
         viewer.SizeMode = SizeMode.Fit;
         break;
   }

   viewer.TransformChanged -= new EventHandler(viewer_TransformChanged);
}

private void viewer_TransformChanged(object sender, EventArgs e)
{
   ImageViewer viewer = sender as ImageViewer;
   string s = string.Format("TransformChanged Event: {0}", viewer.Transform.ToString());
   MessageBox.Show(s);
}
public void ImageViewer_TransformChanged(ImageViewer viewer)
{
   viewer.TransformChanged += new EventHandler(viewer_TransformChanged);

   switch (viewer.SizeMode)
   {
      case SizeMode.Fit:
         viewer.SizeMode = SizeMode.FitAlways;
         break;

      case SizeMode.FitAlways:
         viewer.SizeMode = SizeMode.FitWidth;
         break;

      case SizeMode.FitWidth:
         viewer.SizeMode = SizeMode.Normal;
         break;

      case SizeMode.Normal:
         viewer.SizeMode = SizeMode.Stretch;
         break;

      case SizeMode.Stretch:
         viewer.SizeMode = SizeMode.Fit;
         break;
   }

   viewer.TransformChanged -= new EventHandler(viewer_TransformChanged);
}

Private Sub viewer_TransformChanged(ByVal sender As Object, ByVal e As EventArgs)
   Dim viewer As ImageViewer = TryCast(sender, ImageViewer)
   Dim s As String = String.Format("TransformChanged Event: {0}", viewer.Transform.ToString())
   MessageBox.Show(s)
End Sub
Public Sub ImageViewer_TransformChanged(ByVal viewer As ImageViewer)
   AddHandler viewer.TransformChanged, AddressOf viewer_TransformChanged

   Select Case viewer.SizeMode
      Case SizeMode.Fit
         viewer.SizeMode = SizeMode.FitAlways

      Case SizeMode.FitAlways
         viewer.SizeMode = SizeMode.FitWidth

      Case SizeMode.FitWidth
         viewer.SizeMode = SizeMode.Normal

      Case SizeMode.Normal
         viewer.SizeMode = SizeMode.Stretch

      Case SizeMode.Stretch
         viewer.SizeMode = SizeMode.Fit
   End Select

   RemoveHandler viewer.TransformChanged, AddressOf viewer_TransformChanged
End Sub

TransformChanged Event (ImageViewer)

Reference