Expander control in Form Application

Sure. You can set a normal button to look like the expander button you have in the image. Now, you throw in all your controls inside of a groupbox that you have collapsed. Once the button is pressed (you'd have to check on the state of the groupbox whether it is expanded or collapsed) you can slowly increase its height (and maybe even width) to whatever it was in the original state. And you ought to increment it in steps too.

You could the same so much more easily with WPF, but you'd have to wait for an expert on that subject to respond.

If you do go about and do write that, you will find it worth your while to wrap all of that in a user control that you can use and reuse again and again.

[edit]
of course, looking at Dario's example in the previous post is even easier!