C#编程实现向并口设备发送指令、获取并口设备的状态

using system;
using system.diagnostics;
using system.runtime.interopservices;
using system.text;
using system.windows.forms;

 
namespace parallelport
{
  public partial class form1 : form
  {
    const uint generic_read = 0x80000000;
    const uint generic_write = 0x40000000;
    const uint file_attribute_normal = 0x80;
 
    #region win32 api
    [dllimport("kernel32.dll ")]
    private static extern int createfile(
      string lpfilename,
      uint dwdesiredaccess,
      int dwsharemode,
      int lpsecurityattributes,
      int dwcreationdisposition,
      uint dwflagsandattributes,
      int htemplatefile
      );
 
    [dllimport("kernel32.dll ")]
    private static extern bool writefile(
      int hfile,
      byte[] lpbuffer,
      int nnumberofbytestowrite,
      ref int lpnumberofbyteswritten,
      int lpoverlapped
      );
 
    [dllimport("kernel32.dll ")]
    private static extern bool definedosdevice(
    int dwflags,
    string lpdevicename,
    string lptargetpath);
 
    [dllimport("kernel32.dll ")]
    private static extern bool closehandle(
      int hobject
      );
    [dllimport("kernel32.dll ")]
    private static extern bool readfile(
      int hfile,
      byte[] lpbuffer,
      int nnumberofbytestoread,
      ref int lpnumberofbytesread,
      int lpoverlapped
      );
    #endregion

 
    public form1()
    {
      initializecomponent();
    }
 

    private void button1_click(object sender, eventargs e)
    {
      int ihandle = -1;
      try
      {
        int i = 0;
        //创建实例
        definedosdevice(0x00000001, "lptportname",@"\device\parallel0");
        ihandle = createfile(@"\\.\lptportname",generic_read | generic_write, 0, 0, 3, file_attribute_normal, 0);
        if (ihandle !=-1)
        {
          byte[] mybyte = new byte[3]{ 0x12, 0x14, 0x14 };//要发送的命令（16进制）
          writefile(ihandle, mybyte, mybyte.length, ref i, 0);
          byte[] mybyte1 = new byte[3];
          string content = string.empty;
          int j = 0;
          readfile(ihandle, mybyte1, 3, ref j, 0);
          if (mybyte1 != null)
          {
            foreach(var tempbyte in mybyte1)
            {
              content += tempbyte.tostring();
            }
          }                
          messagebox.show(content);//获取的状态值
        }
        else
        {
          messagebox.show("创建文件失败!");
        }
      }
      catch(exception ex)
      {
        messagebox.show(ex.message);
      }
      finally
      {
        if (ihandle > 0)
        {
          closehandle(ihandle);
        }
      }
    }
  }
}