intX = Screen.PrimaryScreen.Bounds.Width;
intY = Screen.PrimaryScreen.Bounds.Height;
u can use above code get screen width and height
and then pass intx and inty to screen
this.Width = intX ;
this.Height = intY ;
this.Refresh();
but for controls u have use some other way like Anchor codings.
pls refer following link
http://www.c-sharpcorner.com/UploadFile/harishankar2005/AnchoringinWindowsForms11302005051741AM
/AnchoringinWindowsForms.aspx
http://www.c-sharpcorner.com/UploadFile/c5c6e2
/dynamically-resizing-controls-on-windows-forms-using-ancho/
Thanks
AravindB