Trouble with DragDrop event

[Jim R]

I am trying to use Dragdrop event on a control in a VB.NET 2005 app.
The app is getting the DragEnter event, but is never getting a
DragDrop event.
My control has its "AllowDrop" property set to "True". But it seems
to me that I am missing something very fundamental.
Thanks in advance for any help.
Jim

 

[Lloyd Sheen]

You also have to support dragover.

LS

 

[Jim R]

You also have to support dragover.

I have an event handler for Dragover and the code is receiving the
event when there is a drag over. The code is also receiving the
DragEnter event. I do not understand how that effects receiving the
Dragdrop event. Why would I not recieve a DragDrop event?

 

[Guest]

Hello Jim,

I've got a similar Prob, but only with specific controls (toolstripbutton).
In general you should use the dragenter-event to verify wether the control is
a valid target for your D&D operation. To set allowdrop=true only declares
the control as a potential target for ANY d&d-op, in dragenter you'll be able
to specify wether the control accepts a specific d&d-op. You do that by
setting the e.effect to a certain dragdropeffect. Example:

Private Sub DragEnters(ByVal sender As Object, ByVal e As
System.Windows.Forms.DragEventArgs)
If e.Data.GetDataPresent(DataFormats.Text) Then
e.Effect = DragDropEffects.All
Else
e.Effect = DragDropEffects.None
End If
End Sub

This checks if the dragged data is a text and gives the message to the
d&d-op that the handled control is a valid target. Visual expression is the
change of mouse-cursor. If you don't set e.effect (to move, copy, or all), no
dragdrop-event will occur!

HTH

Volker