Treeview Node click behavior

Question

I have a Winform application where I am using TreeView. Some users of this application have a problem that they must double click on a node to expand it. So I added this code to use single click to expand nodes:

Private Sub MyTreeView_NodeMouseClick(sender As System.Object, 
     e As System.Windows.Forms.TreeNodeMouseClickEventArgs) Handles MyTreeView.NodeMouseClick

    If e.Node.IsExpanded Then
        e.Node.Collapse()
    Else
        e.Node.Expand()
    End If

End Sub

This works but I noticed strange behavior regarding clicking on a nodes. I noticed that there are 2 places with different behavior. First place is with +/- symbol and dots next to it (first circle in the picture), second place is a text of the node (second circle):

Normally single click on the first place is enough to expand node and double click must be done on the second place to expand node. Then when I use my code, single click on the second place is enough to expand the node but when I do single click on the first place, the node is expanded and collapsed.

Why the user must do twice more clicks on the second place to expand node? What can I do to expand nodes with single click on both places? Thank you guys!

Answer 1

The plus/minus is still considered part of the Node - and when the user clicks it, your code toggles the expansion but the framework continues and does the same.

Add to your code to not act on the plus/minus:

private static void TreeView_OnNodeMouseClick(object sender, TreeNodeMouseClickEventArgs e)
{
    var hitTest = e.Node.TreeView.HitTest(e.Location);
    if (hitTest.Location == TreeViewHitTestLocations.PlusMinus)
        return;

    if (e.Node.IsExpanded)
        e.Node.Collapse();
    else
        e.Node.Expand();
}