C # Open the system DLL with Run32dll (such as the system Picture Viewer, and place the topmost layer)

  [DllImport ("user32.dll", EntryPoint = "SetWindowPos", CharSet = CharSet.Auto)] static extern bool SetWindowPos ( IntPtr hWnd, IntPtr hwndinsertafter, int X, int Y, int cx, int cy, UINT uFl        AGS);        static readonly IntPtr hwnd_topmost = new IntPtr (-1);        static readonly IntPtr hwnd_notopmost = new IntPtr (-2);        static readonly IntPtr hwnd_top = new IntPtr (0);        Const UINT32 swp_nosize = 0x0001;        Const UINT32 Swp_nomove = 0x0002;        Const UINT32 Swp_nozorder = 0x0004;        Const UINT32 Swp_noredraw = 0x0008;        Const UINT32 swp_noactivate = 0x0010;        Const UINT32 swp_framechanged = 0x0020;        Const UINT32 Swp_showwindow = 0x0040;        Const UINT32 Swp_hidewindow = 0x0080;        Const UINT32 swp_nocopybits = 0x0100;        Const UINT32 Swp_noownerzorder = 0x0200;        Const UINT32 swp_nosendchanging = 0x0400; Const UInt32 Topmost_flags = Swp_nomove |        Swp_nosize; private void Button1_Click (object sender, EventArgs e) {Process process = Process.Start ("rundll32.exe", @ "                        C:\windows\system32\shimgvw.dll,imageview_fullscreen d:\1.jpg "); IntPtr str = process.            Handle; SetWindowPos (this. Handle, hwnd_notopmost, 0, 0, 0, 0, 1 | 2); Last parameter also useful 1 | 4}

C # Open the system DLL with Run32dll (such as the system Picture Viewer, and place the topmost layer)