C#简单的UDP通信例子

1，UDP客户端

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

namespace WindowsFormsApplication14
{
public partial class Form1 : Form
{
UdpClient udpClient;
IPEndPoint ipEndPoint;

public Form1()
{
InitializeComponent();
udpClient = new UdpClient(12345);
ipEndPoint = new IPEndPoint(IPAddress.Parse("192.168.1.241"), 60000);
}

private void button1_Click(object sender, EventArgs e)
{
//byte[] mybyte = Encoding.Default.GetBytes("nihao");

byte[] mybyte = new byte[4];
mybyte[0] = 0x12;
mybyte[1] = 0x00;
mybyte[2] = 0x34;
mybyte[3] = 0x00;

udpClient.Send(mybyte, mybyte.Length,ipEndPoint);
}
}
}

2，UDP服务器

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

namespace WindowsFormsApplication15
{
public partial class Form1 : Form
{
UdpClient udpServer;
IPEndPoint ipEndPoint;

public Form1()
{
InitializeComponent();
udpServer = new UdpClient(23456);
ipEndPoint = new IPEndPoint(new IPAddress(0), 0);
}

private void button1_Click(object sender, EventArgs e)
{

byte[] data = udpServer.Receive(ref ipEndPoint);
MessageBox.Show ( Encoding.Default.GetString(data));
}
}
}

3，读接收缓冲区当前数据个数

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

namespace WindowsFormsApplication15
{
public partial class Form1 : Form
{
UdpClient udpServer;
IPEndPoint ipEndPoint;

public Form1()
{
InitializeComponent();
udpServer = new UdpClient(23456);
ipEndPoint = new IPEndPoint(new IPAddress(0), 0);
}

private void button1_Click(object sender, EventArgs e)
{
byte[] outValue =  BitConverter.GetBytes(0);
udpServer.Client.IOControl(IOControlCode.DataToRead, null, outValue);

MessageBox.Show((BitConverter.ToInt32(outValue,0)).ToString());//发送数据发现此时数据增长，但不会超过8K
//MessageBox.Show((BitConverter.ToString(outValue)).ToString());

}
}
}

 

4，上例有点复杂，看下面的例子，这个例子还可以说明如何设置非阻塞Socket通讯

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

namespace WindowsFormsApplication15
{
public partial class Form1 : Form
{
UdpClient udpServer;
IPEndPoint ipEndPoint;

public Form1()
{
InitializeComponent();
udpServer = new UdpClient(23456);
ipEndPoint = new IPEndPoint(new IPAddress(0), 0);
udpServer.Client.Blocking = false; //设置为非阻塞模式
}

private void button1_Click(object sender, EventArgs e)
{
int buffSizeCurrent;
buffSizeCurrent = udpServer.Client.Available;//取得缓冲区当前的数据的个数

MessageBox.Show(buffSizeCurrent.ToString());
if (buffSizeCurrent > 0)     //有数据时候才读，不然会出异常哦
{
byte[] data = udpServer.Receive(ref ipEndPoint);
MessageBox.Show(Encoding.Default.GetString(data));
}
}
}
}

5，上面的例子是同步非阻塞的例子，但默认是同步阻塞的。除此之外还有异步的通讯方式（事件通知的方式触发），稍微复杂，以后补充。