C#：重定向控制台应用程序输出：如何刷新输出？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/1033648/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
C# : Redirect console application output : How to flush the output?
提问by THX-1138
I am spawning external console application and use async output redirect.
as shown in this SO post
我正在生成外部控制台应用程序并使用异步输出重定向。
如this SO post所示
My problem is it seems that the spawned process needs to produce certain amount of output before I get the OutputDataReceivedevent notification.
我的问题是，在我收到OutputDataReceived事件通知之前，生成的进程似乎需要产生一定数量的输出。
I want to receive the OutputDataReceivedevent as soon as possible.
我想尽快收到OutputDataReceived事件。
I have a bare-bones redirecting application, and here are some observations:
1. When I call a simple 'while(true) print("X");' console application (C#) I receive output event immediately.
2. When I call a 3d party app I am trying to wrap from the command lineI see the line-by-line output.
3. When I call that 3d party app from my bare-bone wrapper (see 1) - the output comes in chunks (about one page size).
我有一个简单的重定向应用程序，这里有一些观察：
1. 当我调用一个简单的 'while(true) print("X");' 控制台应用程序 (C#) 我立即收到输出事件。2. 当我调用 3d 派对应用程序时，我试图从命令行换行，我会看到逐行输出。
3. 当我从我的基本包装器（见 1）中调用那个 3d 派对应用程序时 - 输出是块状的（大约一页大小）。
What happens inside that app?
该应用程序内部会发生什么？
FYI: The app in question is a "USBee DX Data Exctarctor (Async bus) v1.0".
仅供参考：有问题的应用程序是“USBee DX Data Exctarctor (Async bus) v1.0”。
采纳答案by Dean North
I did some more research and have a fix to microsofts Process class. But as my last answer was deleted without a reason, I have had to create a new one.
我做了更多的研究并修复了 microsofts Process 类。但是由于我的最后一个答案被无故删除，我不得不创建一个新答案。
So take this example...
所以拿这个例子...
Create a windows app and stick a rich textbox on the main form, then add this to the form load...
创建一个 Windows 应用程序并在主窗体上粘贴一个富文本框，然后将其添加到窗体加载...
Process p = new Process()
{
StartInfo = new ProcessStartInfo()
{
FileName = "cmd.exe",
CreateNoWindow = true,
UseShellExecute = false,
ErrorDialog = false,
RedirectStandardInput = true,
RedirectStandardOutput = true,
RedirectStandardError = true,
},
EnableRaisingEvents = true,
SynchronizingObject = this
};
p.OutputDataReceived += (s, ea) => this.richTextBox1.AppendText(ea.Data);
p.Start();
p.BeginOutputReadLine();
This will output something like this...
这将输出这样的东西......
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
The OutputDataReceived event is not fired for the last line. After some ILSpying it appears that this is deliberate because the last line does not end with a crlf, it assumes there is more comming and appends it to the start of the next event.
最后一行不会触发 OutputDataReceived 事件。在一些 ILSpying 之后，这似乎是故意的，因为最后一行没有以 crlf 结尾，它假设有更多的到来并将其附加到下一个事件的开始。
To correct this, I have written a wrapper for the Process class and taken some of the required internal classes out with it so that it all works neatly. Here is the FixedProcess class...
为了更正这个问题，我为 Process 类编写了一个包装器，并将一些必需的内部类与它一起取出，以便它们都能正常工作。这是 FixedProcess 类...
using System;
using System.Collections;
using System.IO;
using System.Text;
using System.Threading;
namespace System.Diagnostics
{
internal delegate void UserCallBack(string data);
public delegate void DataReceivedEventHandler(object sender, DataReceivedEventArgs e);
public class FixedProcess : Process
{
internal AsyncStreamReader output;
internal AsyncStreamReader error;
public event DataReceivedEventHandler OutputDataReceived;
public event DataReceivedEventHandler ErrorDataReceived;
public new void BeginOutputReadLine()
{
Stream baseStream = StandardOutput.BaseStream;
this.output = new AsyncStreamReader(this, baseStream, new UserCallBack(this.FixedOutputReadNotifyUser), StandardOutput.CurrentEncoding);
this.output.BeginReadLine();
}
public void BeginErrorReadLine()
{
Stream baseStream = StandardError.BaseStream;
this.error = new AsyncStreamReader(this, baseStream, new UserCallBack(this.FixedErrorReadNotifyUser), StandardError.CurrentEncoding);
this.error.BeginReadLine();
}
internal void FixedOutputReadNotifyUser(string data)
{
DataReceivedEventHandler outputDataReceived = this.OutputDataReceived;
if (outputDataReceived != null)
{
DataReceivedEventArgs dataReceivedEventArgs = new DataReceivedEventArgs(data);
if (this.SynchronizingObject != null && this.SynchronizingObject.InvokeRequired)
{
this.SynchronizingObject.Invoke(outputDataReceived, new object[]
{
this,
dataReceivedEventArgs
});
return;
}
outputDataReceived(this, dataReceivedEventArgs);
}
}
internal void FixedErrorReadNotifyUser(string data)
{
DataReceivedEventHandler errorDataReceived = this.ErrorDataReceived;
if (errorDataReceived != null)
{
DataReceivedEventArgs dataReceivedEventArgs = new DataReceivedEventArgs(data);
if (this.SynchronizingObject != null && this.SynchronizingObject.InvokeRequired)
{
this.SynchronizingObject.Invoke(errorDataReceived, new object[]
{
this,
dataReceivedEventArgs
});
return;
}
errorDataReceived(this, dataReceivedEventArgs);
}
}
}
internal class AsyncStreamReader : IDisposable
{
internal const int DefaultBufferSize = 1024;
private const int MinBufferSize = 128;
private Stream stream;
private Encoding encoding;
private Decoder decoder;
private byte[] byteBuffer;
private char[] charBuffer;
private int _maxCharsPerBuffer;
private Process process;
private UserCallBack userCallBack;
private bool cancelOperation;
private ManualResetEvent eofEvent;
private Queue messageQueue;
private StringBuilder sb;
private bool bLastCarriageReturn;
public virtual Encoding CurrentEncoding
{
get
{
return this.encoding;
}
}
public virtual Stream BaseStream
{
get
{
return this.stream;
}
}
internal AsyncStreamReader(Process process, Stream stream, UserCallBack callback, Encoding encoding)
: this(process, stream, callback, encoding, 1024)
{
}
internal AsyncStreamReader(Process process, Stream stream, UserCallBack callback, Encoding encoding, int bufferSize)
{
this.Init(process, stream, callback, encoding, bufferSize);
this.messageQueue = new Queue();
}
private void Init(Process process, Stream stream, UserCallBack callback, Encoding encoding, int bufferSize)
{
this.process = process;
this.stream = stream;
this.encoding = encoding;
this.userCallBack = callback;
this.decoder = encoding.GetDecoder();
if (bufferSize < 128)
{
bufferSize = 128;
}
this.byteBuffer = new byte[bufferSize];
this._maxCharsPerBuffer = encoding.GetMaxCharCount(bufferSize);
this.charBuffer = new char[this._maxCharsPerBuffer];
this.cancelOperation = false;
this.eofEvent = new ManualResetEvent(false);
this.sb = null;
this.bLastCarriageReturn = false;
}
public virtual void Close()
{
this.Dispose(true);
}
void IDisposable.Dispose()
{
this.Dispose(true);
GC.SuppressFinalize(this);
}
protected virtual void Dispose(bool disposing)
{
if (disposing && this.stream != null)
{
this.stream.Close();
}
if (this.stream != null)
{
this.stream = null;
this.encoding = null;
this.decoder = null;
this.byteBuffer = null;
this.charBuffer = null;
}
if (this.eofEvent != null)
{
this.eofEvent.Close();
this.eofEvent = null;
}
}
internal void BeginReadLine()
{
if (this.cancelOperation)
{
this.cancelOperation = false;
}
if (this.sb == null)
{
this.sb = new StringBuilder(1024);
this.stream.BeginRead(this.byteBuffer, 0, this.byteBuffer.Length, new AsyncCallback(this.ReadBuffer), null);
return;
}
this.FlushMessageQueue();
}
internal void CancelOperation()
{
this.cancelOperation = true;
}
private void ReadBuffer(IAsyncResult ar)
{
int num;
try
{
num = this.stream.EndRead(ar);
}
catch (IOException)
{
num = 0;
}
catch (OperationCanceledException)
{
num = 0;
}
if (num == 0)
{
lock (this.messageQueue)
{
if (this.sb.Length != 0)
{
this.messageQueue.Enqueue(this.sb.ToString());
this.sb.Length = 0;
}
this.messageQueue.Enqueue(null);
}
try
{
this.FlushMessageQueue();
return;
}
finally
{
this.eofEvent.Set();
}
}
int chars = this.decoder.GetChars(this.byteBuffer, 0, num, this.charBuffer, 0);
this.sb.Append(this.charBuffer, 0, chars);
this.GetLinesFromStringBuilder();
this.stream.BeginRead(this.byteBuffer, 0, this.byteBuffer.Length, new AsyncCallback(this.ReadBuffer), null);
}
private void GetLinesFromStringBuilder()
{
int i = 0;
int num = 0;
int length = this.sb.Length;
if (this.bLastCarriageReturn && length > 0 && this.sb[0] == '\n')
{
i = 1;
num = 1;
this.bLastCarriageReturn = false;
}
while (i < length)
{
char c = this.sb[i];
if (c == '\r' || c == '\n')
{
if (c == '\r' && i + 1 < length && this.sb[i + 1] == '\n')
{
i++;
}
string obj = this.sb.ToString(num, i + 1 - num);
num = i + 1;
lock (this.messageQueue)
{
this.messageQueue.Enqueue(obj);
}
}
i++;
}
// Flush Fix: Send Whatever is left in the buffer
string endOfBuffer = this.sb.ToString(num, length - num);
lock (this.messageQueue)
{
this.messageQueue.Enqueue(endOfBuffer);
num = length;
}
// End Flush Fix
if (this.sb[length - 1] == '\r')
{
this.bLastCarriageReturn = true;
}
if (num < length)
{
this.sb.Remove(0, num);
}
else
{
this.sb.Length = 0;
}
this.FlushMessageQueue();
}
private void FlushMessageQueue()
{
while (this.messageQueue.Count > 0)
{
lock (this.messageQueue)
{
if (this.messageQueue.Count > 0)
{
string data = (string)this.messageQueue.Dequeue();
if (!this.cancelOperation)
{
this.userCallBack(data);
}
}
continue;
}
break;
}
}
internal void WaitUtilEOF()
{
if (this.eofEvent != null)
{
this.eofEvent.WaitOne();
this.eofEvent.Close();
this.eofEvent = null;
}
}
}
public class DataReceivedEventArgs : EventArgs
{
internal string _data;
/// <summary>Gets the line of characters that was written to a redirected <see cref="T:System.Diagnostics.Process" /> output stream.</summary>
/// <returns>The line that was written by an associated <see cref="T:System.Diagnostics.Process" /> to its redirected <see cref="P:System.Diagnostics.Process.StandardOutput" /> or <see cref="P:System.Diagnostics.Process.StandardError" /> stream.</returns>
/// <filterpriority>2</filterpriority>
public string Data
{
get
{
return this._data;
}
}
internal DataReceivedEventArgs(string data)
{
this._data = data;
}
}
}
Stick that in your project and then change ...
把它放在你的项目中，然后改变......
Process p = new Process()
{
....
to
到
FixedProcess p = new FixedProcess()
{
....
Now your application should display something like this...
现在您的应用程序应该显示如下内容...
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:\Projects\FixedProcess\bin\Debug>
without needing to make any other changes to your existing code. It is also still async and wrapped up nicely. The one caveat is that now you will get multiple events for large output with potential breaks in-between, so you will need to handle this scenario yourself. Other than that, it should be all good.
无需对现有代码进行任何其他更改。它仍然是异步的并且很好地结束。一个警告是，现在您将获得大量输出的多个事件，中间有潜在的中断，因此您需要自己处理这种情况。除此之外，应该都还好。
回答by David Basarab
Check out this answer.
看看这个答案。
How to send input to the console as if the user is typing?
The idea is that you will receive the output received events when any is thrown after the process is started.
这个想法是，当进程启动后抛出 any 时，您将收到输出接收事件。
回答by joh
It seems as the problem was that the dummy app was written in c# which flushes the output automatically one every println while the 3rd party app was written in c/c++ and therefore only wrote when the stdoutbuffer was full. The only solution which ive found is to make sure the c/c++ app flushes after every print or to set its buffer to 0.
似乎问题在于，虚拟应用程序是用 c# 编写的，它每 println 一次自动刷新输出，而第 3 方应用程序是用 c/c++ 编写的，因此仅在 stdoutbuffer 已满时才写入。我发现的唯一解决方案是确保 c/c++ 应用程序在每次打印后刷新或将其缓冲区设置为 0。
