Jigna:

I am not sure if this is what you are looking for or not.

The following example displays the ContextMenu assigned to
a TreeView when the right mouse button is clicked and released.

This code assumes you have a Form with a TreeView on it. It
is also assumed that the TreeView has a ContextMenu assigned
to its ContextMenu property.

[C#]
Code:
 
private void treeView1_MouseUp(object sender, MouseEventArgs e)
{
   // If the right mouse button was clicked and released,
   // display the context menu assigned to the TreeView. 
   if(e.Button == MouseButtons.Right)
   {
      treeView1.ContextMenu.Show(treeView1, new Point(e.X, e.Y) );      
   }
}
Also, I am not 100% certain, but I think that the mouse pointer must be over a child node and not a parent node.

Good Luck