TcpClient类异步接收数据

傷城~ 2021-06-26 16:06 564阅读 0赞

> `TcpClient`为基于`Socket`构建的用来进行`TCP`通信的简单类，主要用于`TCP`客户端的编写，可以使用同步或者异步。发送接收数据用`NetworkStream`。很多东西摘录自MSDN

## 构造函数 ##

<table> 
 <thead> 
  <tr> 
   <th align="left">名称</th> 
   <th align="left">说明</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td align="left">TcpClient()</td> 
   <td align="left">初始化 TcpClient 类的新实例。</td> 
  </tr> 
  <tr> 
   <td align="left">TcpClient(AddressFamily)</td> 
   <td align="left">使用指定的族初始化 TcpClient 类的新实例。</td> 
  </tr> 
  <tr> 
   <td align="left">TcpClient(IPEndPoint)</td> 
   <td align="left">初始化 TcpClient 类的新实例，并将其绑定到指定的本地终结点。</td> 
  </tr> 
  <tr> 
   <td align="left">TcpClient(String, Int32)</td> 
   <td align="left">初始化 TcpClient 类的新实例并连接到指定主机上的指定端口。</td> 
  </tr> 
 </tbody> 
</table>

> 以上是摘自MSDN上的，其中`AddressFamily`指的是使用指定的协议族，例如IPv4或者IPv6 如果要指定本地端口，用`IPEndPoint`来进行绑定。

## 属性 ##

TcpCient

<table> 
 <thead> 
  <tr> 
   <th align="left">名称</th> 
   <th align="left">说明</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td align="left">Active</td> 
   <td align="left">获取或设置一个值，它指示是否已建立连接。</td> 
  </tr> 
  <tr> 
   <td align="left">Available</td> 
   <td align="left">获取已经从网络接收且可供读取的数据量。</td> 
  </tr> 
  <tr> 
   <td align="left">Client</td> 
   <td align="left">获取或设置基础 Socket。</td> 
  </tr> 
  <tr> 
   <td align="left">Connected</td> 
   <td align="left">获取一个值，该值指示 Socket 的基础 TcpClient 是否已连接到远程主机。</td> 
  </tr> 
  <tr> 
   <td align="left">ExclusiveAddressUse</td> 
   <td align="left">获取或设置 Boolean 值，指定 TcpClient 是否只允许一个客户端使用端口。</td> 
  </tr> 
  <tr> 
   <td align="left">LingerState</td> 
   <td align="left">获取或设置有关关联的套接字的延迟状态的信息。</td> 
  </tr> 
  <tr> 
   <td align="left">NoDelay</td> 
   <td align="left">获取或设置一个值，该值在发送或接收缓冲区未满时禁用延迟。</td> 
  </tr> 
  <tr> 
   <td align="left">ReceiveBufferSize</td> 
   <td align="left">获取或设置接收缓冲区的大小。</td> 
  </tr> 
  <tr> 
   <td align="left">ReceiveTimeout</td> 
   <td align="left">获取或设置在初始化一个读取操作以后 TcpClient 等待接收数据的时间量。</td> 
  </tr> 
  <tr> 
   <td align="left">SendBufferSize</td> 
   <td align="left">获取或设置发送缓冲区的大小。</td> 
  </tr> 
  <tr> 
   <td align="left">SendTimeout</td> 
   <td align="left">获取或设置 TcpClient 等待发送操作成功完成的时间量。</td> 
  </tr> 
 </tbody> 
</table>

NetworkStream

<table> 
 <thead> 
  <tr> 
   <th align="left">名称</th> 
   <th align="left">说明</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td align="left">CanRead</td> 
   <td align="left">获取一个值，该值指示 NetworkStream 是否支持读取</td> 
  </tr> 
  <tr> 
   <td align="left">CanWrite</td> 
   <td align="left">获取一个值，该值指示 NetworkStream 是否支持写入</td> 
  </tr> 
 </tbody> 
</table>

## 主要方法 ##

TcpClient

<table> 
 <thead> 
  <tr> 
   <th align="left">名称</th> 
   <th align="left">说明</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td align="left">BeginConnect(IPAddress, Int32, AsyncCallback, Object)</td> 
   <td align="left">开始一个对远程主机连接的异步请求。远程主机由 IPAddress 和端口号 (Int32) 指定。</td> 
  </tr> 
  <tr> 
   <td align="left">Close()</td> 
   <td align="left">释放此 TcpClient 实例，并请求关闭基础 TCP 连接。</td> 
  </tr> 
 </tbody> 
</table>

NetworkStream

<table> 
 <thead> 
  <tr> 
   <th align="left">名称</th> 
   <th align="left">说明</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td align="left">BeginRead(Byte[], Int32, Int32, AsyncCallback, Object)</td> 
   <td align="left">从 NetworkStream 开始异步读取。</td> 
  </tr> 
  <tr> 
   <td align="left">Close()</td> 
   <td align="left">关闭当前流并释放与之关联的所有资源</td> 
  </tr> 
  <tr> 
   <td align="left">BeginWrite(Byte[], Int32, Int32, AsyncCallback, Object)</td> 
   <td align="left">开始向流异步写入</td> 
  </tr> 
 </tbody> 
</table>

## 流程 ##

### TcpClient读取数据过程 ###

#### TcpClient连接 ####

![在这里插入图片描述][20190910115537812.png]

#### TcpClient已经连接上，NetworkStream读取 ####

![在这里插入图片描述][20190910115616257.png]

#### NetworkStream已经读取完毕，取出数据 ####

![在这里插入图片描述][20190910115653799.png]

### `TcpClient`发送数据流程 ###

> 确保`TcpClient`已经连接的情况下执行

#### TcpClient线程 ####

![在这里插入图片描述][20190910115853632.png]

#### NetworkStream异步发送线程 ####

![在这里插入图片描述][20190910115915630.png]

## 实例 ##

### `TcpClient`连接 ###

private void TcpButton_Click(object sender, EventArgs e)
    { 
        if (TcpButton.Text == "TCP打开")
        { 
            TcpButton.Text = "TCP关闭";
            IPEndPoint targetPoint = new IPEndPoint(TcpUdp.VerifyInputIP(IPTextBox.Text), TcpUdp.VerifyInputPort(TcpTargetPortTextBox.Text));
            int localTcpPort = Int32.Parse(TcpSourcePortTextBox.Text);
            if (localTcpPort > 0)
            { 
                IPEndPoint localEP = new IPEndPoint(IPAddress.Parse("127.0.0.1"), localTcpPort);
                tcp = new TcpClient(localEP);
    
            }
            else
            { 
                tcp = new TcpClient();
            }
            tcp.ReceiveTimeout = 10;
            //异步连接
            tcp.BeginConnect(IPAddress.Parse(IPTextBox.Text), TcpUdp.VerifyInputPort(TcpTargetPortTextBox.Text), Connected, tcp);
        }
        else
        { 
            TcpButton.Text = "TCP打开";
            if ((tcp != null) && (tcp.Connected))
            { 
                ns.Close();
                tcp.Close();
            }
            SetTcpPic(tcp.Connected);
            TcpIsOpen = tcp.Connected;
        }
    }

### `NetworkStream`异步读取 ###

private void Connected(IAsyncResult iar)
    { 
        tcp = (TcpClient)iar.AsyncState;
        tcp.EndConnect(iar);
        //MessageBox.Show("connected");
        SetTcpPic(tcp.Connected);
        TcpIsOpen = tcp.Connected;
        if ((tcp != null) && (tcp.Connected))
        { 
            ns = tcp.GetStream();
    
            StateObject state = new StateObject();
            state.client = tcp;
            NetworkStream stream = state.client.GetStream();
            if (stream.CanRead)
            { 
                byte[] buffer = new byte[tcp.ReceiveBufferSize];
                stream.BeginRead(state.buffer, 0, StateObject.BufferSize, new AsyncCallback(AsyncReadCallBack), state);
            }
        }
    }

### `NetworkStream`读取处理 ###

private void AsyncReadCallBack(IAsyncResult iar)
    { 
        StateObject state = (StateObject)iar.AsyncState;
        if ((state.client == null) || (!state.client.Connected)) return;
        int NumOfBytesRead;
        NetworkStream ns = state.client.GetStream();
        NumOfBytesRead = ns.EndRead(iar);
        if (NumOfBytesRead > 0)
        { 
            byte[] buffer = new byte[NumOfBytesRead];
            Array.Copy(state.buffer, 0, buffer, 0, NumOfBytesRead);
            ReceiveAppend(buffer, TcpUdp.StringType.String);
            ns.BeginRead(state.buffer, 0, StateObject.BufferSize, new AsyncCallback(AsyncReadCallBack), state);
        }
        else
        { 
            ns.Close();
            state.client.Close();
            ns = null;
            state = null;
        }
    }

### `NetworkStream`发送 ###

if (TcpIsOpen)
    { 
        if (ns != null)
        { 
            //ns.Write(buffer, 0, buffer.Length);
            ns.BeginWrite(buffer, 0, buffer.Length, new AsyncCallback(StreamWriteCallBack), ns);
        }
    }
    
    private void StreamWriteCallBack(IAsyncResult iar)
    { 
        NetworkStream ns = (NetworkStream)iar.AsyncState;
        ns.EndWrite(iar);
    }

[20190910115537812.png]: /images/20210626/3c4e457dbeb34bab868f536beace6f97.png
[20190910115616257.png]: /images/20210626/cc151f4fb19f4c718dbfef44b65c6688.png
[20190910115653799.png]: /images/20210626/a9a42ffec71549aaa06850e478fad100.png
[20190910115853632.png]: /images/20210626/ac439302a0774c7ca2193915aa8c1429.png
[20190910115915630.png]: /images/20210626/b8bdc3f093544c8f9aa1097d4d1facfd.png