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How can I disable selection of a TreeNode in a TreeView in VB.NET?

Posted on 2012-04-04
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Last Modified: 2012-04-07
I'm currently implementing a navigation menu using a TreeView control.

In the menu I'm using headers (root nodes) to group menu items. These headers should only have one purpose: double-click collapse/uncollapse. For this reason it should'nt be possible to select and mark the node, but as default this is possible. What can I do to avoid that the headers can be selected? And is there a way to do this by setting TreeNode properties so that selection events doesn't have to be handled?
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Question by:andreas_rafn
6 Comments
 
LVL 25

Expert Comment

by:Luis Pérez
ID: 37806315
Are you using Windows Forms or Web Forms?
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Author Comment

by:andreas_rafn
ID: 37806592
Windows Forms (System.Windows.Forms.TreeView)
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LVL 1

Accepted Solution

by:
IceBird26 earned 300 total points
ID: 37806660
You could add some code in the treeview's BeforeSelect event. Since you don't want any selections on the root nodes, you could do the following:

     private void treeView1_BeforeSelect(object sender, TreeViewCancelEventArgs e)
        {
            if (e.Node.Parent == null)    //if a node doesn't have any parents, it's a root
            {
                e.Cancel = true;
            }
        }



The only drawback is that the node will still be highlighted for a short while while the mouse click is in the down position. Hopefully, your users are not very picky ;)
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LVL 85

Assisted Solution

by:Mike Tomlinson
Mike Tomlinson earned 200 total points
ID: 37806665
Use the BeforeSelect() event and set Cancel to True if the Node does not have a Parent (because it's a root):
    Private Sub TreeView1_BeforeSelect(sender As Object, e As System.Windows.Forms.TreeViewCancelEventArgs) Handles TreeView1.BeforeSelect
        e.Cancel = IsNothing(e.Node.Parent)
    End Sub

Open in new window


*The node does get selected momentarily.  =\
0
 
LVL 85

Expert Comment

by:Mike Tomlinson
ID: 37806670
Hehe...guess I'm 20 seconds too late!  =)
0
 

Author Closing Comment

by:andreas_rafn
ID: 37819014
The fastest submitter gets a little more :) The approach seems good, I'll try to combine it with a handling of the selection color so that the temporary selection will be invisible.
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