TCPClient Error: "System.InvalidOperationExceptio"

Question

我一直在创建一个应该连接到服务器的 TCPClient，但我收到了这个错误：

System.InvalidOperationException: 'The operation is not allowed on non-connected sockets.'

这是我的代码：

Public String IPAddress = "192.168.100.xxx"
Public Int32 Port = 23;
public TcpClient client = new TcpClient();

public void Connect() {
    client.Connect(IPAddress, Port);
    // send first message request to server
    Byte[] msg_data = System.Text.Encoding.ASCII.GetBytes("Hello Server);

    // uses the GetStream public method to return the NetworkStream
    NetworkStream netStream = _client.GetStream();

    // write message to the network
    netStream.Write(msg_data, 0, msg_data.Length);

    // buffer to store the response bytes
    msg_data = new Byte[256];

    // read the first batch of response byte from arduino server
    Int32 bytes = netStream.Read(msg_data, 0, msg_data.Length);
    received_msg = System.Text.Encoding.ASCII.GetString(msg_data, 0, bytes);

    netStream.Close();

}

public void Send() {
    // message data byes to be sent to server
    Byte[] msg_data = System.Text.Encoding.ASCII.GetBytes(_sendMessage);

    // uses the GetStream public method to return the NetworkStream

    // ** Error Here: System.InvalidOperationException: 'The operation is not allowed on non-connected sockets.'
    NetworkStream netStream = client.GetStream(); 

    // write message to the network
    netStream.Write(msg_data, 0, msg_data.Length);

    // buffer to store the response bytes
    msg_data = new Byte[256];

    // read the first batch of response byte from arduino server
    Int32 bytes = netStream.Read(msg_data, 0, msg_data.Length);
    received_msg = System.Text.Encoding.ASCII.GetString(msg_data, 0, bytes);

    netStream.Close(); // close Stream
}

我在创建 NetworkStream netStream = client.GetStream(); 的新实例时遇到错误。一直在努力寻找导致错误的原因，我认为它以某种方式关闭了上面的连接。

一切都在 class 中，必须在软件中的任何地方调用。

Answer 1

client.GetStream() 的实现方式如下：

return new NetworkStream(this.Client, true);

而 true 表示如果流是 disposed/closed，它也会 closes/disconnects socket/client。您应该可以通过直接调用

来避免这种情况

var netStream = new NetworkStream(client.Client, false);

更好的是：

NetworkStream netStream = client.GetStream();
…
netSteam.Dlose();

确保即使出现错误也始终关闭流：

using (var netStream = new NetworkStream(client.Client, false))
{
  …
}

TCPClient Error: "System.InvalidOperationExceptio"

TCPClient Error: "System.InvalidOperationExceptio"

c#

tcpclient