[英]Chat application in C#
我已經嘗試過使用此代碼制作聊天應用程序。 當我運行該應用程序時,出現Exception: A request to send or receive data was disallowed because the socket is not connected
並且(在使用sendto調用在數據報套接字上發送時) no address was supplied
Exception: A request to send or receive data was disallowed because the socket is not connected
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;
using System.Net.Sockets;
namespace client_chatApplication
{
public partial class Form1 : Form
{
Socket sck;
EndPoint epLocal, epRemote;
public Form1()
{
InitializeComponent();
sck = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
sck.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
textLocalIP.Text = GetLocalIp();
textFriendsIP.Text = GetLocalIp();
}
//to get the local ip address
private string GetLocalIp()
{
IPHostEntry host;
host = Dns.GetHostEntry(Dns.GetHostName());
foreach (IPAddress ip in host.AddressList)
{
if (ip.AddressFamily == AddressFamily.InterNetwork)
{
return ip.ToString();
}
}
return "127.0.0.1";
}
public void MessageCallBack(IAsyncResult aresult)
{
try
{
int size = sck.EndReceiveFrom(aresult, ref epRemote);
if (size > 0)
{
byte[] receivedData = new byte[1464];
receivedData = (byte[])aresult.AsyncState;
ASCIIEncoding eEncoding = new ASCIIEncoding();
string receivedMessage = eEncoding.GetString(receivedData);
listMessage.Items.Add("fiend" + receivedMessage);
}
byte[] buffer = new byte[1500];
sck.BeginReceiveFrom(buffer, 0, buffer.Length, SocketFlags.None, ref epRemote, new AsyncCallback(MessageCallBack), buffer);
}
catch (Exception exp)
{
MessageBox.Show(exp.ToString());
}
}
private void label1_Click(object sender, EventArgs e)
{
}
private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
}
private void button2_Click(object sender, EventArgs e)
{
}
private void textLocalIP_TextChanged(object sender, EventArgs e)
{
try
{
System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding();
byte[] msg = new byte[1500];
msg = enc.GetBytes(textMessage.Text);
sck.Send(msg);
listMessage.Items.Add("yoy" + textMessage.Text);
textMessage.Clear();
}
catch (Exception exp)
{
MessageBox.Show(exp.ToString());
}
}
private void button1_Click(object sender, EventArgs e)
{
try
{
epLocal = new IPEndPoint(IPAddress.Parse(textLocalIP.Text), Convert.ToInt32(textLocalPort.Text));
sck.Bind(epLocal);
epRemote = new IPEndPoint(IPAddress.Parse(textFriendsIP.Text), Convert.ToInt32(textFriendsPort.Text));
sck.Bind(epRemote);
byte[] buffer = new byte[1500];
Socket dataSocket = AsyncSocket.EndAccept(_IAsyncResult);
sck.BeginReceiveFrom(buffer, 0, buffer.Length, SocketFlags.None, ref epRemote, new AsyncCallback(MessageCallBack), buffer);
button1.Text = "connected";
button1.Enabled = false;
button2.Enabled = true;
textMessage.Focus();
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
}
}
您創建了套接字,但創建后未將其綁定到端口。 您想發送數據時將其綁定。
僅當您要發送數據時綁定是不正確的行為。
您還只需要將套接字綁定到本地IPEndpoint
。 當您使用功能SendTo()發送數據IPEndpoint
將使用遠程IPEndpoint
。
使用套接字涉及以下基本步驟:
創建套接字
完成前三個步驟后,便建立了套接字連接,您將需要使用該連接進行發送和接收系統調用。這意味着,列出的前三個點僅“執行一次”,您將使用它來進行多次發送和接收呼叫,直到最終關閉連接。
該鏈接將進一步幫助您。
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