C# Code:

/// <summary>
/// 监视器开关控制
/// </summary>
public class MonitorTool
{
   [DllImport("user32.dll")]
   public static extern IntPtr SendMessage(
   IntPtr hWnd,
   uint msg,
   uint wParam,
   int lParam);
   
   //系统消息
   private const uint WM_SYSCOMMAND = 0x112;
   
   //关闭显示器的系统命令
   private const int SC_MONITORPOWER = 0xF170;
   
   //2为PowerOff, 1为省电状态，-1为开机
   private const int MonitorPowerOff = 2;
   
   /// <summary>
   /// 关闭显示器
   /// </summary>
   public static void PowerOff(IntPtr hWnd)
   {
      SendMessage(
      hWnd,
      WM_SYSCOMMAND,
      SC_MONITORPOWER,
      2
      );
   }
   
   /// <summary>
   /// 打开显示器
   /// </summary>
   public static void PowerOn(IntPtr hWnd)
   {
      SendMessage(
      hWnd,
      WM_SYSCOMMAND,
      SC_MONITORPOWER,
      -1
      );
   }
   
}

//来源:C/S框架网(www.csframework.com) QQ:23404761