Adding a dropdown to a button in C#

Question

Hi All,

I am trying to implement a dropdown-button control in C#
which provides a list of actions.

Many Microsoft applicaitons use this kind of control. One
example is in the file open dialog box (goto
File -> Open -> File). The Open button has a dropdown
icon that gives two choices ('Open' and 'Open With').

Anybody has any idea of how to implement this control?