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using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.IO.Ports;

namespace BluetoothTest
{
    public class Printer
    {
        SerialPort server = new SerialPort();
        private string _portName = "COM6";//蓝牙一般默认为com6


        /// <summary>
        /// 获取或设置端口名称
        /// </summary>
        public string PortName
        {
            get
            {
                _portName = server.PortName;
                return _portName;
            }
            set
            {
                _portName = value;
                server.PortName = _portName;
            }
        }
        /// <summary>
        /// 端口是否已经打开
        /// </summary>
        public bool IsOpen
        {
            get
            {
                return server.IsOpen;
            }
        }
        /// <summary>
        /// 构造方法初始化串口参数
        /// </summary>
        public Printer()
        {//初始化各个参数
            server.BaudRate = 9600;//波特率
            server.Parity = 0;//校检位
            server.DataBits = 8;//数据位
            server.StopBits = StopBits.One;//停止位
            server.PortName = _portName;//端口名称
            server.WriteTimeout = -1;//超时时间
            server.ReadTimeout = -1;//超时时间
        }
        /// <summary>
        /// 打开端口
        /// </summary>
        /// <returns></returns>
        public bool OpenPort()
        {
            try
            {
                if (!server.IsOpen)
                {//关闭的
                    server.Open();
                }
                else
                {//打开的
                    //server.Close();
                    //server.Open();
                }
                return true;
            }
            catch(Exception ex)
            { return false; }
        }
        /// <summary>
        /// 发送数据
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public bool SendDataToPort(string str,out string mes)
        {
            try
            {
                byte[] OutBuffer;//数据

                int BufferSize;
                Encoding targetEncoding;

               



                //将[UNICODE编码]转换为[GB码]，仅使用于简体中文版mobile
                targetEncoding = Encoding.GetEncoding(0);    //得到简体中文字码页的编码方式，因为是简体中文操作系统，参数用0就可以，用936也行。
                BufferSize = targetEncoding.GetByteCount(str); //计算对指定字符数组中的所有字符进行编码所产生的字节数          
                OutBuffer = new byte[BufferSize];
                OutBuffer = targetEncoding.GetBytes(str);       //将指定字符数组中的所有字符编码为一个字节序列,完成后outbufer里面即为简体中文编码

                byte[] cmdData = new byte[BufferSize+100];

                //初始化打印机
                cmdData[0] = 0x1B;
                cmdData[1] = 0x40;
                //设置字符顺时旋转180度
                cmdData[2] = 0x1B;
                cmdData[3] = 0x56;
                cmdData[4] = 0;


                for (int i = 0; i < BufferSize; i++)
                {
                    cmdData[5 + i] = OutBuffer[i];
                }


                //向打印机发送[GB码]数据
                server.Write(cmdData, 0, BufferSize + 5);
                //server.WriteLine(str);

                //初始化指令1B 40
                cmdData[0] = 0x1B;
                cmdData[1] = 0x40;
                //打印并走纸指令
                cmdData[2] = 0x1B;
                cmdData[3] = 0x64;
                cmdData[4] = 0x02;

                server.Write(cmdData, 0, 5);
                mes = "";
                return true;
            }
            catch(Exception ex)
            {
                mes = ex.Message;
                return false;
            }
        }
        /// <summary>
        /// 十六进制转换字节数组
        /// </summary>
        /// <param name="s"></param>
        /// <returns></returns>
        private byte[] HexStringToByteArray(string s)
        {
            s = s.Replace(" ", "");
            byte[] buffer = new byte[s.Length / 2];
            for (int i = 0; i < s.Length; i += 2)
                buffer[i / 2] = (byte)Convert.ToByte(s.Substring(i, 2), 16);
            return buffer;
        }
        /// <summary>
        /// 字节数组转换十六进制
        /// </summary>
        /// <param name="data"></param>
        /// <returns></returns>
        private string ByteArrayToHexString(byte[] data)
        {
            StringBuilder sb = new StringBuilder(data.Length * 3);
            foreach (byte b in data)
                sb.Append(Convert.ToString(b, 16).PadLeft(2, '0').PadRight(3, ' '));
            return sb.ToString().ToUpper();
        }

        public void ClosePort()
        {
            server.Close();           
        }
       
    }
}

3.接下在项目窗体上的使用，看看下面的代码：

 using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace BluetoothTest
{
public partial class frmMain : Form
{
public frmMain()
{
InitializeComponent();
}
Printer printer = new Printer();
private void menuItem4_Click(object sender, EventArgs e)
{
//退出
printer.ClosePort();
Application.Exit();
}

private void menuItem2_Click(object sender, EventArgs e)
{
//打印
if (tbxBody.Text.Length == 0)
return;

setEnabled(false);
if (!printer.IsOpen)//只有在端口关闭的时候才能设置
printer.PortName = drpPort.GetItemText(drpPort.SelectedItem);
if (!printer.OpenPort())
{
MessageBox.Show("无法打开端口" + drpPort.GetItemText(drpPort.SelectedItem));
}
string mes = "";
if (!printer.SendDataToPort(tbxBody.Text,out mes))
{
MessageBox.Show("发送数据失败" + drpPort.GetItemText(drpPort.SelectedItem) + " " + mes);
}

setEnabled(true);

}
private void setEnabled(bool b)
{
menuItem1.Enabled = b;
menuItem3.Enabled = b;
}
private void frmMain_Load(object sender, EventArgs e)
{
//初始化
drpPort.SelectedIndex = 1;
}
}
}