How do I maximize my main window

To maximize the main window, you can get the handle of the main window in the new process, and then send a SC_MAXIMIZE system command message to it. You can get the handle through the Process.MainWindowHandle property. To send a message you should use the DllImportAttribute attribute to import the API function. This is a sample code:

public class WinAPI
{
	public const int WM_SYSCOMMAND = 0x0112;
	public const int SC_MAXIMIZE = 0xF030;

	[DllImportAttribute ('user32.dll')]
	public static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam);
}

Process p = new Process();
p.StartInfo.FileName = @'D:\Program Files\test.exe';
p.Start();
WinAPI.SendMessage(p.MainWindowHandle, WinAPI.WM_SYSCOMMAND, WinAPI.SC_MAXIMIZE,0);

(from lion_noreply@microsoft.com on microsoft.public.dotnet.framework.windowsforms)