c# - 将数据从类传递到表单列表框 |聊天客户端

Question

我目前正在开发一个聊天程序。它包含一个 Form(MainWindow) 和一个 class(TCPServerConnector)。MainWindow 是包含两个文本框、两个按钮和一个列表框的 UI。

在第一个文本框中，您必须输入要连接的服务器 ip，然后单击“连接”按钮。第二个文本框包含您的书面文本，第二个按钮发送此文本。列表框应该显示程序从服务器接收到的所有聊天/文本，但我没有让它工作。

Main-Form 初始化 TCPServerConnector 的对象并将 IP 和文本传递给它。但是当你收到一些文本时，类必须将收到的文本传递给表单。

我尝试使用委托(delegate)(以前从未使用过)，但并没有解决我的问题，我只是遇到了一些关于跨线程的异常。

同时创建 MainWindow 的新实例，因为它不引用 Main-Form 的旧实例。

我已经添加了下面类的代码，希望有人能解决我的问题；)

---

主窗体:

public partial class MainWindow : Form
{

    public MainWindow()
    {
        InitializeComponent();
    }

    TCPServerConnector TestConnection = new TCPServerConnector();

    private void Form1_Load(object sender, EventArgs e)
    {
    }

    private void srvConnect_Click(object sender, EventArgs e)
    {
        TestConnection.ConnectToServer(srvConnectionIP.Text.ToString());
    }

    private void srvSend_Click(object sender, EventArgs e)
    {
        TestConnection.SendEnteredString(srvTextToSend.Text.ToString());
    }

    private void FormMain_Closing(object sender, System.ComponentModel.CancelEventArgs e)
    {
        TestConnection.CloseConnection();
    }
}

---

在“OnRecievedData”方法中，我添加了一个消息框来显示收到的文本，因为目前，我无法将其添加到表单列表框。

TCPServerConnector 类:

class TCPServerConnector
{
    private Socket m_sock;
    private byte[] m_byBuff = new byte[256];

    public void ConnectToServer(string ServerAddress)
    {
        try
        {
            if (m_sock != null && m_sock.Connected)
            {
                m_sock.Shutdown(SocketShutdown.Both);
                System.Threading.Thread.Sleep(10);
                m_sock.Close();
            }

            m_sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

            IPEndPoint epServer = new IPEndPoint(IPAddress.Parse(ServerAddress), 399);

            m_sock.Blocking = false;
            AsyncCallback onconnect = new AsyncCallback(OnConnect);
            m_sock.BeginConnect(epServer, onconnect, m_sock);
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

    public void OnConnect(IAsyncResult ar)
    {
        Socket sock = (Socket)ar.AsyncState;

        try
        {
            if (sock.Connected)
                SetupRecieveCallback(sock);
            else
                MessageBox.Show("Unable to establish connection");
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

    public void OnRecievedData(IAsyncResult ar)
    {
        Socket sock = (Socket)ar.AsyncState;

        try
        {
            int nBytesRec = sock.EndReceive(ar);
            if (nBytesRec > 0)
            {
                string sRecieved = Encoding.ASCII.GetString(m_byBuff, 0, nBytesRec);
                MessageBox.Show(sRecieved); //TO SHOW IF SOMETHING HAPPENED. HERE IS MY PROBLEM
                SetupRecieveCallback(sock);
            }
            else
            {
                Console.WriteLine("Client {0}, disconnected", sock.RemoteEndPoint);
                sock.Shutdown(SocketShutdown.Both);
                sock.Close();
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

    public void SetupRecieveCallback(Socket sock)
    {
        try
        {
            AsyncCallback recieveData = new AsyncCallback(OnRecievedData);
            sock.BeginReceive(m_byBuff, 0, m_byBuff.Length, SocketFlags.None, recieveData, sock);
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

    public void SendEnteredString(string EnteredData)
    {
        if (m_sock == null || !m_sock.Connected)
        {
            MessageBox.Show("You have to be connected to send something.");
            return;
        }

        try
        {
            Byte[] byteDateLine = Encoding.ASCII.GetBytes(EnteredData.ToCharArray());
            m_sock.Send(byteDateLine, byteDateLine.Length, 0);
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

    public void CloseConnection()
    {
        if (m_sock != null && m_sock.Connected)
        {
            m_sock.Shutdown(SocketShutdown.Both);
            m_sock.Close();
        }
    }
}

Answer 1

在您的连接器类中创建事件 DataReceived 并在收到数据时引发它:

public class TCPServerConnector
{
    public event Action<string> DataReceived; // event

    public void OnRecievedData(IAsyncResult ar)
    {    
        try
        {
            Socket sock = (Socket)ar.AsyncState;
            int nBytesRec = sock.EndReceive(ar);
            if (nBytesRec > 0)
            {
                string sRecieved = Encoding.ASCII.GetString(m_byBuff, 0, nBytesRec);
                if (DataReceived != null) // check if subscribed
                    DataRecieved(sRecieved); // raise event with data

                SetupRecieveCallback(sock);
            }
            else
            {
                Console.WriteLine("Client {0}, disconnected", sock.RemoteEndPoint);
                sock.Shutdown(SocketShutdown.Both);
                sock.Close();
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

    // rest of code is same
}

并以主形式订阅这个事件:

public MainWindow()
{
    InitializeComponent();
    TestConnection.DataRecieved += TestConnection_DataRecieved;
}

private void TestConnection_DataRecieved(string data)
{ 
   if (InvokeRequired) // check if you are on main thread
   {
       // invoke same method on main thread
       Invoke((MethodInvoker)(() => TestConnection_DataRecieved(data)));
       return;
   }

   // show data in listbox
}

注意:您可以使用 EventHandler<TEventArgs>事件的委托(delegate)类型(就像 Microsoft 所做的那样)并创建 protected 方法 OnDataReceived(string data)用于引发事件。但是我用了Action<string>为简单起见委托(delegate)。