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);
        }
      }
    }
  }
}