Question

If user has multiple screens,

how can I start application in primary screen or chosen screen at start up

Answer 1

Heres the basic code. It uses WinForms but I dont know of a pure WPF solution.

using System;
using System.Windows;
using System.Windows.Forms;

namespace Foo
{
    public class WindowUtility
    {
        public static void MoveToMonitor(Window window, int monitorId, bool maximize)
        {
            Screen[] screens = Screen.AllScreens;

            int screenId = monitorId - 1;

            if (screens.Length > 1 && screenId < screens.Length)
            {
                var screen = screens[screenId];
                var area = screen.WorkingArea;

                if (maximize)
                {
                    window.Left = area.Left;
                    window.Top = area.Top;
                    window.Width = area.Width;
                    window.Height = area.Height;
                }
                else
                {
                    window.Left = area.Left;
                    window.Top = area.Top;
                }
            }
        }
    }
}