Sometimes clicking on a TreeView node doesn't select it

Hi;

I have this case where when I click on a line in my TreeView, it selects it
for a second, and then moves the selection back to the previous selection.
Usually I have to click 3 times to get it to stick - then it's fine from then
on.

The tree is not set to accept drag/drop. HideSelection=false, otherwaise all
is standard.

This is the only event I have for the control - and it is the only control
in the form:

private void Tree_MouseDown(object sender,
System.Windows.Forms.MouseEventArgs e)
{

TreeNode node = treeDB.GetNodeAt(e.X, e.Y);
if (node == null)
return;
RootNode root = node.Tag as RootNode;
if (root == null)
return;

DoDragDrop(new DragDropData(app, root), DragDropEffects.Copy);
}

Any ideas?

--
thanks - dave

v-jetan
Tue Jun 14 04:40:51 CDT 2005

Hi Dave,

Thanks for your post.

Your code snippet is unable to run in my sample project, because you did
not provide the definition for type RootNode and DragDropData.
I suggest you provide a complete runable sample code snippet with steps or
a sample project to help us reproduce out this issue. Then we can help you
better. Thanks

Best regards,
Jeffrey Tan
Microsoft Online Partner Support
Get Secure! - www.microsoft.com/security
This posting is provided "as is" with no warranties and confers no rights.

thielen
Tue Jun 14 12:15:09 CDT 2005

I placed a very simple project that does this at
http://www.windward.net/tree.zip

The only control in a form is a TreeView and the only event handler for that
control is MouseDown where it calls DoDragDrop().

If you click on a tree line release the mouse (without moving it) and then
move the mouse - the selection immediately moves back to the original line.

Any ideas?

--
thanks - dave


""Jeffrey Tan[MSFT]"" wrote:

> Hi Dave,
>
> Thanks for your post.
>
> Your code snippet is unable to run in my sample project, because you did
> not provide the definition for type RootNode and DragDropData.
> I suggest you provide a complete runable sample code snippet with steps or
> a sample project to help us reproduce out this issue. Then we can help you
> better. Thanks
>
> Best regards,
> Jeffrey Tan
> Microsoft Online Partner Support
> Get Secure! - www.microsoft.com/security
> This posting is provided "as is" with no warranties and confers no rights.
>
>

v-jetan
Wed Jun 15 03:17:43 CDT 2005

Hi Dave,

Thanks for your feedback.

Yes, with your sample project, I reproduced out this problem on my side.

After doing some research, I found that it seems that DoDragDrop method
calling in MouseDown event will prevent TreeView's selected node from
changing. If we set some debug output in treeView1_MouseDown,
treeView1_MouseUp and treeView1_BeforeSelect events, we will see that:
1. Without the DoDragDrop method calling in MouseDown, all 3 events will
fire
2. With DoDragDrop method calling in MouseDown, treeView1_BeforeSelect do
not fire, and the selection will to back to its original selected treenode.

Currently, I still did not find the root cause for this issue. However, I
want to tell that for ListView and TreeView controls, we should call
DoDragDrop method in ItemDrag event to enable the drag&drop, this is
documented in:
"Performing Drag-and-Drop Operations in Windows Forms"
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbcon/html/
vbtskStartingDragOperations.asp

In the above document, you will see that:
"Note Certain controls have custom drag-specific events. The ListView and
TreeView controls, for example, have an ItemDrag event."

So we should use ItemDrag event to start the drag&drop operation. Also,
placing DoDragDrop method calling in ItemDrag event will not cause this
problem.

Hope this helps.
================================================
Thank you for your patience and cooperation. If you have any questions or
concerns, please feel free to post it in the group. I am standing by to be
of assistance.

Best regards,
Jeffrey Tan
Microsoft Online Partner Support
Get Secure! - www.microsoft.com/security
This posting is provided "as is" with no warranties and confers no rights.

thielen
Wed Jun 15 07:45:02 CDT 2005

That fixed it - thanks - dave

--
thanks - dave


""Jeffrey Tan[MSFT]"" wrote:

> Hi Dave,
>
> Thanks for your feedback.
>
> Yes, with your sample project, I reproduced out this problem on my side.
>
> After doing some research, I found that it seems that DoDragDrop method
> calling in MouseDown event will prevent TreeView's selected node from
> changing. If we set some debug output in treeView1_MouseDown,
> treeView1_MouseUp and treeView1_BeforeSelect events, we will see that:
> 1. Without the DoDragDrop method calling in MouseDown, all 3 events will
> fire
> 2. With DoDragDrop method calling in MouseDown, treeView1_BeforeSelect do
> not fire, and the selection will to back to its original selected treenode.
>
> Currently, I still did not find the root cause for this issue. However, I
> want to tell that for ListView and TreeView controls, we should call
> DoDragDrop method in ItemDrag event to enable the drag&drop, this is
> documented in:
> "Performing Drag-and-Drop Operations in Windows Forms"
> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbcon/html/
> vbtskStartingDragOperations.asp
>
> In the above document, you will see that:
> "Note Certain controls have custom drag-specific events. The ListView and
> TreeView controls, for example, have an ItemDrag event."
>
> So we should use ItemDrag event to start the drag&drop operation. Also,
> placing DoDragDrop method calling in ItemDrag event will not cause this
> problem.
>
> Hope this helps.
> ================================================
> Thank you for your patience and cooperation. If you have any questions or
> concerns, please feel free to post it in the group. I am standing by to be
> of assistance.
>
> Best regards,
> Jeffrey Tan
> Microsoft Online Partner Support
> Get Secure! - www.microsoft.com/security
> This posting is provided "as is" with no warranties and confers no rights.
>
>

v-jetan
Thu Jun 16 02:07:12 CDT 2005

You are welcome

Best regards,
Jeffrey Tan
Microsoft Online Partner Support
Get Secure! - www.microsoft.com/security
This posting is provided "as is" with no warranties and confers no rights.