(C#) — How to disable Close Button in Windows Form

 private const int CP_NOCLOSE_BUTTON = 0x200;
 protected override CreateParams CreateParams
 {
     get
     {
        CreateParams myCp = base.CreateParams;
        myCp.ClassStyle = myCp.ClassStyle | CP_NOCLOSE_BUTTON ;
        return myCp;
     }
 }