并口

    public class LPTControl
    {
        [StructLayout(LayoutKind.Sequential)]
        private struct OVERLAPPED
        {
            int Internal;
            int InternalHigh;
            int Offset;
            int OffSetHigh;
            int hEvent;
        }
        [DllImport("kernel32.dll")]
        private static extern int CreateFile(
         string lpFileName,
         uint dwDesiredAccess,
         int dwShareMode,
         int lpSecurityAttributes,
         int dwCreationDisposition,
         int dwFlagsAndAttributes,
         int hTemplateFile
         );
        [DllImport("kernel32.dll")]
        private static extern bool WriteFile(
         int hFile,
         byte[] lpBuffer,
         int nNumberOfBytesToWrite,
         ref int lpNumberOfBytesWritten,
         ref OVERLAPPED lpOverlapped
         );
        [DllImport("kernel32.dll")]
        private static extern bool CloseHandle(
         int hObject
         );
        private int iHandle;
        public bool Open()
        {
            iHandle = CreateFile("lpt1", 0x40000000, 0, 0, 3, 0, 0);
            if (iHandle != -1)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
        public bool Write(String Mystring)
        {
            if (iHandle != -1)
            {
                OVERLAPPED x = new OVERLAPPED();
                int i = 0;

                byte[] mybyte = System.Text.Encoding.Default.GetBytes(Mystring);
                bool b = WriteFile(iHandle, mybyte, mybyte.Length, ref i, ref x);
                return b;
            }
            else
            {
                throw new Exception("不能连接到打印机!");
            }
        }
        public bool Write(byte[] mybyte)
        {
            if (iHandle != -1)
            {
                OVERLAPPED x = new OVERLAPPED();
                int i = 0;
                WriteFile(iHandle, mybyte, mybyte.Length,
                 ref i, ref x);
                return true;
            }
            else
            {
                throw new Exception("不能连接到打印机!");
            }
        }
        public bool Close()
        {
            return CloseHandle(iHandle);
        }
    }