big dynamic form

Agreed. I've gotten into the habit of using forms ONLY as presentation layer and moving all biz logic into classes or separate libraries where applicable (this doesn't apply to small simple single form apps - cost vs. reward and all). Spend some time writing Code-Behind ASP.NET code and you'll gain a newfound love of presentation/logic separation. In addition, you can probably do what you want by exposing a public delegate or simply casting your control's Parent object to the type your form is Form2 frm = (Form2)this.Parent (it is parent, right?)

What kind of method it is? Obviously, it has to be a public method and you access in the same way you access other classes. Create an instance of the class and call the method. Is there any thing am I missing here? You would be better off if put all non-form related code (logic) in a seperate class and share the class members among multiple forms.