C＃ - StreamReader.ReadLine不能正常工作！ [英] C# - StreamReader.ReadLine does not work properly!

问题描述

只要我一直在努力实现的东西 BufferedStreamReader 确实在Java中。我有一个套接字流开，只是想读它在一个面向行的方式 - 线，由线

Simply I have been trying to implement what BufferedStreamReader does in Java. I have a socket stream open and just want to read it in a line-oriented fashion - line by line.

我有以下的服务器 - code。

I have the following server-code.

while (continueProcess)
        {
            try
            {
                StreamReader reader = new StreamReader(Socket.GetStream(), Encoding.UTF8);
                string command = reader.ReadLine();
                if (command == null)
                    break;

                OnClientExecute(command);
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }

和下面的客户端 - code：

And the following client-code:

TcpClient tcpClient = new TcpClient();
        try
        {
            tcpClient.Connect("localhost", serverPort);
            StreamWriter writer = new StreamWriter(tcpClient.GetStream(), Encoding.UTF8);
            writer.AutoFlush = true;
            writer.WriteLine("login>user,pass");
            writer.WriteLine("print>param1,param2,param3");
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }
        finally
        {
            tcpClient.Close();
        }

服务器只读取第一行（登录＆gt;用户，通过），然后的ReadLine 返回null！

The server reads only the very first line (login>user,pass) and then ReadLine returns null!

什么是实现这一目标的面向行的读者，因为它是在Java中的 BufferedStreamReader 的最简单的方法？ ：■

What's the easiest way of achieving this line-oriented reader as it is in Java's BufferedStreamReader? :s

推荐答案

一个典型的行阅读器是一样的东西：

A typical line-reader is something like:

using(StreamReader reader = new StreamReader(Socket.GetStream(), Encoding.UTF8)) {
    string line;
    while((line = reader.ReadLine()) != null) {
        // do something with line
    }
}

（注意使用，以确保我们的Dispose（）它，即使我们得到一个错误，循环）

(note the using to ensure we Dispose() it even if we get an error, and the loop)

如果你愿意，你可以摘要（关注点分离）与迭代器块：

If you want, you could abstract this (separation of concerns) with an iterator block:

static IEnumerable<string> ReadLines(Stream source, Encoding encoding) {
    using(StreamReader reader = new StreamReader(source, encoding)) {
        string line;
        while((line = reader.ReadLine()) != null) {
            yield return line;
        }
    }
}

（注意，我们已经转移到这一个功能，去掉了做什么，以收益回报，这将创建一个迭代器（一个懒洋洋地迭代，非缓冲状态机）替换它

(note we've moved this into a function and removed the "do something", replacing it with "yield return", which creates an iterator (a lazily iterated, non-buffering state machine)

我们会再消费这是简单的：

We would then consume this as simply as:

foreach(string line in ReadLines(Socket.GetStream(), Encoding.UTF8)) {
    // do something with line
}

现在我们处理code并不需要担心的如何的读线 - 简单的给的行的顺序，做一些与他们

Now our processing code doesn't need to worry about how to read lines - simply given a sequence of lines, do something with them.

注意使用（的Dispose（））适用于的TcpClient 过;你应该检查的IDisposable 的习惯;例如（仍包括您的错误记录）：

Note that the using (Dispose()) applies to TcpClient too; you should make a habit of checking for IDisposable; for example (still including your error-logging):

using(TcpClient tcpClient = new TcpClient()) {
    try {
       tcpClient.Connect("localhost", serverPort);
       StreamWriter writer = new StreamWriter(tcpClient.GetStream(), Encoding.UTF8);
       writer.AutoFlush = true;
       writer.WriteLine("login>user,pass");
       writer.WriteLine("print>param1,param2,param3");
    } catch (Exception ex) {
        Console.Error.WriteLine(ex.ToString());
    }
}

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