Pending Method-优快云博客

本文链接：https://blog.youkuaiyun.com/hartkevin/article/details/5296640

本文介绍 .NET Framework 中 TcpListener 类的 Pending 方法，该方法用于判断是否有待处理的连接请求。文章提供了 C# 示例代码，演示如何使用 Pending 方法检查客户端连接请求，并在存在连接请求时调用 AcceptTcpClient 方法。

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Pending Method

.NET Framework Class Library

TcpListener.Pending Method

Determines if there are pending connection requests.

[C#]
public bool Pending();

Return Value

true if connections are pending; otherwise, false.

Exceptions

Exception Type	Condition
InvalidOperationException	The listener has not been started with a call to Start.

Remarks

This non-blocking method determines if there are any pending connection requests. Because the AcceptSocket and AcceptTcpClient methods block execution until Start has queued an incoming connection request, the Pending method can be used to determine if connections are available before attempting to accept them.

Example

[C#] The following example checks the Pending method. If a connection request is waiting to be accepted, then then a call to AcceptTcpClient is made.

[C#]

      try{
// Use the Pending method to poll the underlying socket instance for client connection requests.
    IPAddress ipAddress = Dns.Resolve("localhost").AddressList[0];
TcpListener tcpListener = new TcpListener(ipAddress, portNumber);
tcpListener.Start();

if (!tcpListener.Pending()) {

Console.WriteLine("Sorry, no connection requests have arrived");

             }
             else{

     //Accept the pending client connection and return a TcpClient object initialized for communication.
     TcpClient tcpClient = tcpListener.AcceptTcpClient();
     // Using the RemoteEndPoint property.
     Console.WriteLine("I am listening for connections on " +
                                 IPAddress.Parse(((IPEndPoint)tcpListener.LocalEndpoint).Address.ToString()) +
                                    "on port number " + ((IPEndPoint)tcpListener.LocalEndpoint).Port.ToString());

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework