[2005] [RESOLVED] Prevent TreeNode from Collapsing when DoubleClicked but...

Hi,

I have got a standard Windows Forms Treeview which contains some nodes.

I am using NodeMouseDoubleClick event to get the node and then get the ID of the node and show a form containing data that belongs to the ID.

What I am stuck at is when I double click any node, it Collapses or Expands depending on it's previous state.

I want to Prevent TreeNode from Collapsing or Expanding when DoubleClicked but allow when user clicks that tiny "+" or "-" button in front of the node.

Is this possible? Is so then could someone guide me to the solution please?

Cheers :)

The treeview exposes some events for when a node is expanded/collapsed.

Look at the BeforeCollapse and BeforeExpand events

Using the event args in those events you can decide if you want to set e.cancel to true to prevent it from happening.

The solution may include the need to set a boolean variable in your double click code, so you know if you should set cancel to true in these events.

Thanks Kleinma, I tried those but the trouble is when I double click a node, the before collapse event fires before that and thus expanding or collapsing the node and then the double click event happening!

It's not ideal but you could simply undo the operation on a double-click:

vb.net Code:

Private Sub TreeView1_NodeMouseDoubleClick(ByVal sender As Object, _
                                           ByVal e As TreeNodeMouseClickEventArgs) Handles TreeView1.NodeMouseDoubleClick
    If e.Node.IsExpanded Then
        e.Node.Collapse()
    Else
        e.Node.Expand()
    End If
End Sub

Other than that I think you'd have to get into trapping Windows messages to know when the node was expanding or collapsing due to a double-click.

Thanks Jim,

I knew it would come down to this solution, I had it already but I just didn't wanted to go to the WM_Messages path!

I have put this code for now, in C# actually.

Code:

---

        private void tvwChildren_NodeMouseDoubleClick(object sender, TreeNodeMouseClickEventArgs e)
        {
            string sEntityID = String.Empty;

            if (e.Node != null)
            {
                sEntityID = e.Node.Name.ToString();
            }

            try
            {
                tvwChildren.SuspendLayout();

                if (e.Node.IsExpanded)
                {
                    e.Node.Collapse();
                }
                else
                {
                    e.Node.Expand();
                }
            }
            finally
            {
                tvwChildren.ResumeLayout(true);
            }
        }  // tvwChildren_NodeMouseDoubleClick

---

Thanks for the heads up. :)