C# StreamReader ReadLine() 在第二次尝试时挂起，除非线程退出

Question

我从另一个开发人员那里继承了下面的代码，它向外部系统发出请求。

我使用不同的“方法”参数值（来自 BackgroundWorker）调用 GenerateRequest 方法，所有这些都可以正常工作。然后当我进行第二次调用时，它仍然适用于除一个“方法”值之外的所有值（它还包含“参数”值的不同值，我将在下面也包括调用），它挂在 StreamReader ReadLine( ） 称呼。但是，如果我在允许 10-20 秒的时间内调试并逐步执行代码，输出会显示一些“线程 0xd0f0 已退出，代码为 0 (0x0)”的消息，然后代码就可以工作了。

我觉得我正在执行这项工作的线程有问题，但我无法弄清楚，请帮助。

这每次都有效；

   ClientParameters parameters = new ClientParameters();
   string request = requestHandler.GenerateRequest("GetFunctions", parameters);

这仅在第一次有效，除非我调试并逐步执行，让线程有时间退出。

ClientParameters parameters = new ClientParameters();
        parameters.Filter = new ClientParametersFilter();
        parameters.Filter.Demographics = "";
        parameters.Filter.Medication = "";
        parameters.Filter.MinEffectiveDate = DateTime.Now;
        parameters.Filter.MaxEffectiveDate = DateTime.MaxValue;
        string request = null;
        try
        {
            request = requestHandler.GenerateRequest("GetRecord", parameters);
        }
        catch(Exception e)
        {
            // log error
            return null;
        }

Hear 是发出请求的类；

public class MyRequestHandler : IRequestHandler{
public string GenerateRequest(string method, ClientParameters parameters)
{
    ClientIntegrationRequest request = new ClientIntegrationRequest();
    request.APIKey = ApplicationSettings.APIKey;
    request.Function = method;
    request.FunctionVersion = 1.0M;
    request.RequestUID = DateTime.Now.ToString();
    request.DeviceID = ApplicationSettings.DeviceId;
    request.DeviceVersion = ApplicationSettings.DeviceVersion;
    request.FunctionParameters = parameters;

    XmlSerializer ser = new XmlSerializer(typeof(ClientIntegrationRequest));
    string xml;
    using (MemoryStream m = new MemoryStream())
    {
        ser.Serialize(m, request);
        // reset to 0
        m.Position = 0;
        xml = new StreamReader(m).ReadToEnd();
    }

    try
    {
        TcpClient tcpClient = new TcpClient("127.0.0.1", ApplicationSettings.Port);
        NetworkStream netStream = tcpClient.GetStream();
        if (netStream.CanWrite)
        {
            xml = xml + "\n";
            Byte[] sendBytes = Encoding.UTF8.GetBytes(xml);
            netStream.Write(sendBytes, 0, sendBytes.Length);
            netStream.Flush();
        }
        else
        {
            tcpClient.Close();
            netStream.Close();
            return null;
        }
        netStream = tcpClient.GetStream();
        if (netStream.CanRead)
        {
            StreamReader l_textReader = new StreamReader(netStream);
            string str = l_textReader.ReadLine(); // Here's the issue
            l_textReader.Close();           
            tcpClient.Close();
            netStream.Close();
            return str.ToString();
        }
        else
        {
            tcpClient.Close();
            netStream.Close();
            return null;
        }
    }
    catch (SocketException e)
    {
        // log error
        return null;
    }
    catch (Exception e)
    {
        // log error
        return null;
    }
}}

Answer 1

如果您查看 Microsoft 示例：https://docs.microsoft.com/en-us/dotnet/api/system.net.sockets.tcpclient.getstream?view=netframework-4.7.2 可以看到代码通过读取字节数组返回的内容的低级代码读取客户端流：

if (netStream.CanRead)
{
    // Reads NetworkStream into a byte buffer.
    byte[] bytes = new byte[tcpClient.ReceiveBufferSize];

    // Read can return anything from 0 to numBytesToRead. 
    // This method blocks until at least one byte is read.
    netStream.Read (bytes, 0, (int)tcpClient.ReceiveBufferSize);

    // Returns the data received from the host to the console.
    string returndata = Encoding.UTF8.GetString (bytes);

    Console.WriteLine ("This is what the host returned to you: " + returndata);

}

你可以试试这个阅读方法吗？