Hi,

Setting diagram.MiddleButtonActions = MouseButtonActions.Pan will let you pan with middle button. If you need to allow that only with C key down, try toggling the property value from KeyDown/Up event handlers.

Regards,
Slavcho
Mindfusion

I'm not sure if I follow MiddleButtonActions = Pan lets you pan with middle button, and is not one of the properties you meantioned trying in first post. Or do you mean you also want to use ScrollViewer's scrollbars with the middle button and prevent left-button-dragging them?

try this -

private void OnDiagramKeyDown(object sender, KeyEventArgs e)
{
	if (e.Key == Key.C)
	{
		// anything but Pan to prevent left-button pan
		diagram.Behavior = Behavior.DoNothing;

		// enable middle-button drag
		diagram.MiddleButtonActions = MouseButtonActions.Pan;
	}
} 

Regards,
Slavcho
Mindfusion

Based on the solution above, my use case is stuck again:
1. When C key is continuously pressed & along with it when mouse (with middle pressed) is moved then no notification is needed on UI.
2. When only C key is pressed and released a notification is needed on UI.

To do that, i tried to attached OnMouseDown handler to update a local property, but continuously pressing C key will Not allow OnMouseDown's handler to execute.


Example:

bool wasMouseUsedtoPan;

private void OnMouseDown(object sender, MouseButtonEventArgs e)
    {
//doesn't come here
if (e.MiddleButton == MouseButtonState.Pressed)
   wasMouseUsedtoPan= true;
}


internal void OnDiagramKeyDown(object sender, KeyEventArgs e)
      {
      if (e.Key == Key.C)
      {       
        diagram.Behavior = Behavior.DoNothing;
        diagram.MiddleButtonActions = MouseButtonActions.Pan;
}
}

I was also thinking it in this way; If we pan and scroll the diagram what property (like viewport! etc) of the diagram changes so that i can attached my event with that accordingly!

Thanks a lot.

@Slavcho: That helped. Its working perfectly now . Thanks for your time and patience