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How to manage keyboard input

Thread ID:





91111 Nov 4,2009 12:25 PM UTC Nov 9,2009 09:41 AM UTC WinForms 2
Tags: Diagram
Declan O'Loughlin
Asked On November 4, 2009 12:25 PM UTC

When a node is selected on the diagram, if the user presses the delete key the node is removed.

I have tried using the keydown event and setting e.handled = true when the keycode = delete, but that does not have any effect.

Has anyone any ideas how I might achieve this.

Declan O'Loughlin
Replied On November 4, 2009 04:53 PM UTC


When I did a bit more digging I found the following
1. Add a handler for EventSink_NodeCollectionChanging
2. Record the delete key press using PreviewKeyDown

AddHandler Me.dgmProcesss.Model.EventSink.NodeCollectionChanging, AddressOf EventSink_NodeCollectionChanging

Private Sub EventSink_NodeCollectionChanging(ByVal e As CollectionExEventArgs)
If deletePressed Then
e.Cancel = True
deletePressed = False
End If
End Sub

Dinesh M [Syncfusion]
Replied On November 9, 2009 09:41 AM UTC

Hi Declan,

Thanks for the update. You can also use the following code to prevent a node from being deleted.

AddHandler diagram.Model.EventSink.NodeCollectionChanging, AddressOf EventSink_NodeCollectionChanging

Private Sub EventSink_NodeCollectionChanging(ByVal evtArg As CollectionExEventArgs)
If (evtArg.ChangeType = CollectionExChangeType.Remove) Then
evtArg.Cancel = True
End If
End Sub



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