[DllImport("user32.dll")]
private static extern bool
SetForegroundWindow(IntPtr hWnd);
[DllImport("user32.dll")]
private static extern bool ShowWindowAsync(IntPtr hWnd, int nCmdShow);
[DllImport("user32.dll")]
private static extern bool IsIconic(IntPtr hWnd);
// 消息函数
[DllImport("user32.dll", EntryPoint = "PostMessageA")]
public static extern bool PostMessage(IntPtr hWnd, int Msg, int wParam, int lParam);

[DllImport("user32.dll")]
public static extern IntPtr FindWindow(string strclassName, string strWindowName);
[DllImportAttribute("user32.dll")]
public static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam);

public const int WM_SYSCOMMAND = 0x0112;
public const int SC_MAXIMIZE = 0xF030;

private string exeName = "SaoMiaoApp";
public void SetForm()
{
  Process[] processes = Process.GetProcessesByName(exeName);

  if (processes.Length > 0)
  {
 IntPtr hWnd = processes[0].MainWindowHandle;

 if (IsIconic(hWnd))
   ShowWindowAsync(hWnd, 9);// 9就是SW_RESTORE标志，表示还原窗体
 //SendMessage(hWnd, WM_SYSCOMMAND, SC_MAXIMIZE, 0);
 SetForegroundWindow(hWnd);
  }
  else
  {
 Process.Start(exeName + ".exe");
  }
}