C#控制打印机(直接发送打印机命令到打印机)

//代码：
//
using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
namespace LPTControls
{
public class LPTControls
{
[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 nNumberOfBytesToWriter, out int lpNumberOfBytesWriten, out OVERLAPPED lpOverLapped);
[DllImport("kernel32.dll")]
private static extern bool CloseHandle(int hObject);
private int iHandle;
//打开LPT 端口
public bool Open()
{
iHandle = CreateFile("lpt1", 0x40000000, 0, 0, 3, 0, 0);
if (iHandle != -1)
{
return true;
}
else
{
return false;
}
}
//打印函数，参数为打印机的命令或者其他文本！
public bool Write(string MyString)
{
if (iHandle != 1)
{
int i;
OVERLAPPED x;
byte[] mybyte = System.Text.Encoding.Default.GetBytes(MyString);
return WriteFile(iHandle, mybyte, mybyte.Length, out i, out x);
}
else
{
throw new Exception("端口未打开~！");
}
}
//关闭打印端口
public bool Close()
{
return CloseHandle(iHandle);
}
}
}
//*************************************************************************************
//使用方法
private void button1_Click(object sender, EventArgs e)
{
LPTControls.LPTControls lpt = new LPTControls.LPTControls();
string mycommanglines = System.IO.File.ReadAllText("print.txt");//print.txt里写了条码机的命令
lpt.Open();
lpt.Write(mycommanglines);
lpt.Close();
}