读卡器的Win32 Dll调用

 unsafe class Program
 {
     [DllImport("mwhrf_bj.dll")]
     public static extern int rf_card(int icdev, Byte _Mode, UInt64* _Snr);

     [DllImport("mwhrf_bj.dll")]
     public static extern int Open_USB();

     [DllImport("mwhrf_bj.dll")]
     public static extern int Close_USB(int icdev);

     [DllImport("mwhrf_bj.dll")]
     public static extern int rf_beep(int icdev, UInt32 _Msec);

     static void Main(string[] args)
     {
         int devID = Open_USB();
         Console.WriteLine("打开端口成功");
         while (true)
         {
             UInt64 cardSN;
             int flag= rf_card(devID, (Byte)0x00, &cardSN);//寻一次卡 然后卡片必须拿开
             //int flag= rf_card(devID, (Byte)0x00, &cardSN);//在卡片不拿走的情况连续询卡
             if (flag != )
             {
                 rf_beep(devID, );
                 Console.WriteLine("寻卡成功，卡号是{0}", cardSN);
             }
             Thread.Sleep();
         }
         Close_USB(devID);
         Console.WriteLine("关闭端口成功");
     }
 }