Hello,
you can do this by using the Screen class.
To make sure your principal form opens on the first screen:
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
var form1 = new Form1();
form1.StartPosition = FormStartPosition.Manual;
form1.Location = Screen.PrimaryScreen.Bounds.Location;
Application.Run(form1);
}
To open your second form on the secondary screen (or any other if more than 2):
int screenToUse = 1;
Screen[] screens = Screen.AllScreens;
var form2 = new Form2();
form2.Location = screens[screenToUse].WorkingArea.Location;
form2.Show();
Valery.