C#向并口设备发送指令以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);
}
}
}
}
}