How can I show a context menu only when the user has clicked the root node in a TreeView?

Question

I have a TreeView and a Context Menu. I want to show the Context Menu ONLY when I right click on the ROOT node and not the child nodes.

This is what I have so far. This shows the Context Menu even when I right click on the child nodes. How can I change this so that the Menu shows only when I right click on the root node? Is it possible?

if(e.Button == MouseButtons.Right)
{
    // Select the clicked node
    treeView1.SelectedNode = treeView1.GetNodeAt(e.X, e.Y);

    if(treeView1.SelectedNode != null)
    {
        myContextMenuStrip.Show(treeView1, e.Location)
    }
}

Answer 1

Yes, it's possible, but you'll need to add some logic to your if statements that verifies the node the user clicked on is a root node.

But how do we find out if it's a root node? Well, thinking it through, we can define a root node as one that does not have any parents. So you can simply check the Parent property of the TreeNode and make sure that it is null.

Modify your code to look something like this:

if (e.Button == MouseButtons.Right)
{
    // Select the clicked node
    treeView1.SelectedNode = treeView1.GetNodeAt(e.X, e.Y);

    if (treeView1.SelectedNode != null && treeView.SelectedNode.Parent == null)
    {
        myContextMenuStrip.Show(treeView1, e.Location)
    }
}

You want to retain the check that the node itself is not null, because you don't want to show the context menu when they haven't clicked on a node, but you need to add the check for a parent, because that tells you whether or not it's a root node. The way you indicate that programmatically is using a logical AND, which is the && operator in C#.

Answer 2

You can also use the Level property:

http://msdn.microsoft.com/EN-US/library/386b25wy(v=VS.110,d=hv.2).aspx

If e.Button = MouseButtons.Right Then
  ' Select the clicked node
  treeView1.SelectedNode = treeView1.GetNodeAt(e.X, e.Y)

  If treeView1.SelectedNode.Level = 0 Then
    myContextMenuStrip.Show(treeView1, e.Location)
  End If
End If

Answer 3

Check that the node you clicked on is the root node instead of checking for it being null.