Using the MouseDown event with Windows Forms Treeview controls

Provided by Dan Haught, FMS Executive Vice President

This example code shows two important treeview concepts:

1. How to get a handle to the node that was clicked on.
2. How to set focus to a node when it is right-clicked.

Example

To use this code, create a new Windows Form object and add a treeview control. Add the following code to the form’s class. Then hook up the MouseDown event to the appropriate code (VB.NET or C#).

    ' VB

    Private Sub TreeView1_MouseDown( _

    ByVal sender As System.Object, _

    ByVal e As System.Windows.Forms.MouseEventArgs) _

    Handles TreeView1.MouseDown

   

        Dim NodeClicked As TreeNode

   

        ' Get the node clicked on

        NodeClicked = Me.TreeView1.GetNodeAt(e.X, e.Y)

   

        ' Was a node clicked on

        If Not NodeClicked Is Nothing Then

            Console.WriteLine("Node is: " & NodeClicked.Text)

        Else

            Console.WriteLine("No node clicked.")

        End If

 

        ' By default, right-clicking on a node does not set

        ' focus to that node. This is especially important when

        ' you want to use a ContextMenu control and associate

        ' it with a TreeView.  This code shows how to do it.

        If e.Button = MouseButtons.Right Then

            Me.TreeView1.SelectedNode = NodeClicked

        End If

   

    End Sub

 

    // C#

    private void TreeViewMouseDown (object sender, MouseEventArgs e)

    {

        TreeNode nodeClicked;

        // Get the node clicked on

        nodeClicked = this.TreeView1.GetNodeAt(e.X, e.Y);

 

        // Was the node clicked on?

        if (! (nodeClicked == null))

            Console.WriteLine ("Node is: " + nodeClicked.Text);

        else

            Console.WriteLine("No node clicked.");

 

        // By default, right-clicking on a node does not set focus to

        // that node. This is especially important when you want to

        // use a ContextMenu control and associate it with a TreeView. 

        // This code shows how to do it.

        if (e.Button == MouseButtons.Right)

            this.TreeView1.SelectedNode = nodeClicked;

    }