VC# : Messy long form code file, what to do?

Lets see if I can explain what I need... I got a form with a lot of visual stuff inside a couple of Tabs inside a "TabControl", being used to Delphi I remember I could put some sort of "frame" inside my main form which pointed back to other forms in order to be able to handle the code better. Is there anything similar in Visual C#? I mean, right now I'm using #region Bla - #endregion to group my code better for each "TabPage". Is it possible to like, cut a source code file into two or more pieces? Right now, I'm getting this huge huge long source code file of my "main" form which isn't too fun.