class LptControl  {  private string LptStr = "lpt1";  public LptControl(string l_LPT_Str)  {  LptStr = l_LPT_Str;  }  [StructLayout(LayoutKind.Sequential)]  private struct OVERLAPPED  {  int Internal;  int InternalHigh;  int Offset;  int OffSetHigh;  int hEvent;  }  //调用DLL.  [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;  /// <summary>  /// 打开端口  /// </summary>  /// <returns></returns>  public bool Open()  {  iHandle = CreateFile(LptStr, 0x40000000, 0, 0, 3, 0, 0);  // iHandle = CreateFile(LptStr, GENERIC_WRITE, 0, 0, OPEN_EXISTING, 0, 0);  if (iHandle != -1)  {  return true;  }  else  {  return false;  }  }  /// <summary>  /// 打印字符串，通过调用该方法可以打印需要的字符串  /// </summary>  /// <param name="Mystring"></param>  /// <returns></returns>  public bool Write(String Mystring)  {  //如果端口为打开，则提示，打开，则打印  if (iHandle != -1)  {  OVERLAPPED x = new OVERLAPPED();  int i = 0;  //byte[] mybyte = System.Text.Encoding.Default.GetBytes(Mystring);  byte[] mybyte = Encoding.GetEncoding("GB2312").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!");  }  }  /// <summary>  /// 打印命令，通过参数，可以打印小票打印机的一些命令，比如换行，行间距，打印位图等。  /// </summary>  /// <param name="mybyte"></param>  /// <returns></returns>  public bool Write(byte[] mybyte)  {  //如果端口为打开，则提示，打开，则打印  if (iHandle != -1)  {  OVERLAPPED x = new OVERLAPPED();  int i = 0;  return WriteFile(iHandle, mybyte, mybyte.Length, ref i, ref x);  }  else  {  throw new Exception("不能连接到打印机!");  }  }  /// <summary>  /// 关闭端口  /// </summary>  /// <returns></returns>  public bool Close()  {  return CloseHandle(iHandle);  }  }  

/// <summary>  /// 打印图片方法  /// </summary>  public void PrintOne()  {  //获取图片  Bitmap bmp = new Bitmap(pictureBox1.Image);  //设置字符行间距为n点行  //byte[] data = new byte[] { 0x1B, 0x33, 0x00 };  string send = "" + (char)(27) + (char)(51) + (char)(0);  byte[] data = new byte[send.Length];  for (int i = 0; i < send.Length; i++)  {  data[i] = (byte)send[i];  }  lc.Write(data);  data[0] = (byte)'\x00';  data[1] = (byte)'\x00';  data[2] = (byte)'\x00';    // Clear to Zero.
  Color pixelColor;  //ESC * m nL nH d1…dk   选择位图模式  // ESC * m nL nH  byte[] escBmp = new byte[] { 0x1B, 0x2A, 0x00, 0x00, 0x00 };  escBmp[2] = (byte)'\x21';  //nL, nH  escBmp[3] = (byte)(bmp.Width % 256);  escBmp[4] = (byte)(bmp.Width / 256);  //循环图片像素打印图片  //循环高  for (int i = 0; i < (bmp.Height / 24 + 1); i++)  {  //设置模式为位图模式
               lc.Write(escBmp);  //循环宽  for (int j = 0; j < bmp.Width; j++)  {  for (int k = 0; k < 24; k++)  {  if (((i * 24) + k) < bmp.Height)  // if within the BMP size
                       {  pixelColor = bmp.GetPixel(j, (i * 24) + k);  if (pixelColor.R == 0)  {  data[k / 8] += (byte)(128 >> (k % 8));  }  }  }  //一次写入一个data，24个像素
                   lc.Write(data);  data[0] = (byte)'\x00';  data[1] = (byte)'\x00';  data[2] = (byte)'\x00';    // Clear to Zero.
               }  //换行，打印第二行  byte[] data2 = { 0xA };  lc.Write(data2);  } // data  lc.Write("\n\n");  }  

for (int i = 0; i < ((bmp.Height + 7) / 8); i++)  {  _serialPort.Write(escBmp, 0, escBmp.Length);  for (int j = 0; j < bmp.Width; j++)  {  for (int k = 0; k < 8; k++)  {  if (((i * 8) + k) < bmp.Height)  // if within the BMP size
                        {  pixelColor = bmp.GetPixel(j, (i * 8) + k);  if (pixelColor.R == 0)  {  data[0] += (byte)(128 >> k);  }  }  }  _serialPort.Write(data, 0, 1);  data[0] = (byte)'\x00'; // Clear to Zero.
                }