[转载]C#中串口通信编程

原文及源代码位置:http://bbs.msproject.cn/default.aspx?g=posts&t=333

原文作者：ivanx

转载自：http://bbs.msproject.cn/

[翻译]
Tapan Dantre.著Serial Communication using C# and Whidbey


[简介]

本文将介绍如何在.NET平台下使用C#创建串口通信程序，.NET 2.0提供了串口通信的功能，其命名

空间是System.IO.Ports。这个新的框架不但可以访问计算机上的串口，还可以和串口设备进行通信。

我们将使用标准的RS <!----><st1:chmetcnv w:st="on" tcsc="0" numbertype="1" negative="False" hasspace="True" sourcevalue="232" unitname="C">232 C</st1:chmetcnv> 在PC间通信。它工作在全双工模式下，而且我们不打算使用任何的握手

或流控制器，而是使用无modem连接。

命名空间

System.IO.Ports命名空间中最重用的是SerialPort 类。

创建SerialPort 对象

通过创建SerialPort 对象，我们可以在程序中控制串口通信的全过程。
我们将要用到的SerialPort 类的方法：
ReadLine()：从输入缓冲区读一新行的值，如果没有，会返回NULL
WriteLine(string)：写入输出缓冲
Open()：打开一个新的串口连接
Close()：关闭<!----><o:p></o:p>

Code: <o:p></o:p>

//create a <st1:place w:st="on"><st1:placename w:st="on">Serial</st1:placename> <st1:placetype w:st="on">Port</st1:placetype></st1:place> object
SerialPort sp = new SerialPort ();<o:p></o:p>

默认情况下，DataBits 值是8，StopBits 是1，通信端口是COM1。这些都可以在下面的属性中重新设置

：

BaudRate：串口的波特率
StopBits：每个字节的停止位数量
ReadTimeout：当读操作没有完成时的停止时间。单位，毫秒

还有不少其它公共属性，自己查阅MSDN。

串口的硬件知识

在数据传输的时候，每个字节的数据通过单个的电缆线传输。包包括开始位，数据，结束为。一旦

开始位传出，后面就会传数据，可能是5，6，7或8位，就看你的设定了。发送和接收必须设定同样

的波特率和数据位数。

无猫模式

没有Modem模式的电缆只是简单地交叉传送和接收线。同样DTR & DSR, 和 RTS & CTS也需要交叉。

RS232针图

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这里，我们三条线。互连2和3（一段的2pin连接3pin），连接两端的5pin。

[示例程序]

主程序

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如果想使用默认属性，按“Save Status”按钮，如果想改变属性按“Property”。它会弹出下图：

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设定好之后，可以通信了。

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<v:shape id="_x0000_i1029" style="WIDTH: 301.5pt; HEIGHT: 228.75pt" alt="image" type="#_x0000_t75"><v:imagedata o:href="http://bbs.msproject.cn/upload_image/de6e558f-2406-41ab-8ae3-89ea7e4acd6d.jpg" src="file:///C:\DOCUME~1\WHITEL~1\LOCALS~1\Temp\msohtml1\01\clip_image005.jpg"></v:imagedata></v:shape>


主窗口的代码<o:p></o:p>

Code: <o:p></o:p>

#region Using directives

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Windows.Forms;
using System.IO.Ports;

#endregion

namespace Serialexpample
{
    partial class Form1 : Form
    {
        //create instance of property page
        //property page is used to set values for stop bits and
        //baud rate

        PropertyPage pp = new PropertyPage();

        //create an Serial Port object
        SerialPort sp = new SerialPort();

        public Form1()
        {
            InitializeComponent();
        }
            
        private void propertyButton_Click(object sender, EventArgs e)
        {
            //show property dialog
            pp.ShowDialog();

            propertyButton.Hide();
        }

        private void sendButton_Click(object sender, EventArgs e)
        {
            try
            {
                //write line to serial port
                sp.WriteLine(textBox.Text);
                //clear the text box
                textBox.Text = "";
            }
            catch (System.Exception ex)
            {
                baudRatelLabel.Text = ex.Message;
            }

        }

        private void ReadButton_Click(object sender, EventArgs e)
        {
            try
            {
                //clear the text box
                textBox.Text = "";
                //read serial port and displayed the data in text box
                textBox.Text = sp.ReadLine();
            }
            catch(System.Exception ex)
            {
                baudRatelLabel.Text = ex.Message;
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            MessageBox.Show("Do u want to Close the App");
            sp.Close();
        }

        private void startCommButton_Click(object sender, EventArgs e)
        {
            startCommButton.Hide();
            sendButton.Show();
            readButton.Show();
            textBox.Show();
        }

        //when we want to save the status(value)
        private void saveStatusButton_Click_1(object sender, EventArgs e)
        {
            //display values
            //if no property is set the default values
            if (pp.bRate == "" && pp.sBits == "")
            {
                dataBitLabel.Text = "BaudRate = " + sp.BaudRate.ToString();
                readTimeOutLabel.Text = "StopBits = " + sp.StopBits.ToString();
            }
            else
            {
                dataBitLabel.Text = "BaudRate = " + pp.bRate;
                readTimeOutLabel.Text = "StopBits = " + pp.sBits;
            }

            parityLabel.Text = "DataBits = " + sp.DataBits.ToString();
            stopBitLabel.Text = "Parity = " + sp.Parity.ToString();
            readTimeOutLabel.Text = "ReadTimeout = " +
                      sp.ReadTimeout.ToString();

            if (propertyButton.Visible == true)
                propertyButton.Hide();
            saveStatusButton.Hide();
            startCommButton.Show();

            try
            {
                //open serial port
                sp.Open();
                //set read time out to 500 ms
                sp.ReadTimeout = 500;
            }
            catch (System.Exception ex)
            {
                baudRatelLabel.Text = ex.Message;
            }
        }
    }
}<o:p></o:p>

属性设置对话框代码：<o:p></o:p>

Code: <o:p></o:p>

#region Using directives

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

#endregion

namespace Serialexpample
{
    partial class PropertyPage : Form
    {
        //variables for storing values of baud rate and stop bits
        private string baudR="";
        private string stopB="";

        //property for setting and getting baud rate and stop bits
        public string bRate
        {
            get
            {
                return baudR;
            }
            set
            {
                baudR = value;
            }
        }

        public string sBits
        {
            get
            {
                return stopB;
            }
            set
            {
                stopB = value;
            }
        }

        public PropertyPage()
        {
            InitializeComponent();
        }

        private void cancelButton_Click(object sender, EventArgs e)
        {
            this.bRate = "";
            this.sBits = "";
            //close form
            this.Close();
        }

        private void okButton_Click_1(object sender, EventArgs e)
        {
            //here we set the value for stop bits and baud rate.
            this.bRate = BaudRateComboBox.Text;
            this.sBits = stopBitComboBox.Text;
            //
            this.Close();

        }
    }
}<o:p></o:p>