我有以下代码:
info = new System.Diagnostics.ProcessStartInfo("TheProgram.exe", String.Join(" ", args));
info.CreateNoWindow = true;
info.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
info.RedirectStandardOutput = true;
info.UseShellExecute = false;
System.Diagnostics.Process p = System.Diagnostics.Process.Start(info);
p.WaitForExit();
Console.WriteLine(p.StandardOutput.ReadToEnd()); //need the StandardOutput contents
我知道我正在启动的进程的输出大约有7MB长。在Windows控制台中运行它可以正常工作。不幸的是,从编程的角度来看,它会无限期地挂在WaitForExit上。还要注意,对于较小的输出(比如3KB),这段代码不会挂起。
ProcessStartInfo中的内部StandardOutput是否可能不能缓冲7MB?如果是,我该怎么办?如果不是,我做错了什么?
我试图通过考虑Mark Byers, Rob, stevejay的回答,创建一个类来解决你使用异步流读取的问题。这样做,我意识到有一个与异步流程输出流读取相关的错误。
我在微软报告了这个漏洞:https://connect.microsoft.com/VisualStudio/feedback/details/3119134
简介:
You can't do that:
process.BeginOutputReadLine(); process.Start();
You will receive System.InvalidOperationException : StandardOut has
not been redirected or the process hasn't started yet.
============================================================================================================================
Then you have to start asynchronous output read after the process is
started:
process.Start(); process.BeginOutputReadLine();
Doing so, make a race condition because the output stream can receive
data before you set it to asynchronous:
process.Start();
// Here the operating system could give the cpu to another thread.
// For example, the newly created thread (Process) and it could start writing to the output
// immediately before next line would execute.
// That create a race condition.
process.BeginOutputReadLine();
============================================================================================================================
Then some people could say that you just have to read the stream
before you set it to asynchronous. But the same problem occurs. There
will be a race condition between the synchronous read and set the
stream into asynchronous mode.
============================================================================================================================
There is no way to acheive safe asynchronous read of an output stream
of a process in the actual way "Process" and "ProcessStartInfo" has
been designed.
对于您的情况,您最好使用其他用户建议的异步读取。但是您应该意识到,由于竞态条件,您可能会错过一些信息。
https://stackoverflow.com/a/17600012/4151626的信用归于EM0
我的应用程序的其他解决方案(包括EM0)仍然处于死锁状态,这是由于内部超时以及派生应用程序同时使用StandardOutput和standderror。以下是对我有效的方法:
Process p = new Process()
{
StartInfo = new ProcessStartInfo()
{
FileName = exe,
Arguments = args,
UseShellExecute = false,
RedirectStandardOutput = true,
RedirectStandardError = true
}
};
p.Start();
string cv_error = null;
Thread et = new Thread(() => { cv_error = p.StandardError.ReadToEnd(); });
et.Start();
string cv_out = null;
Thread ot = new Thread(() => { cv_out = p.StandardOutput.ReadToEnd(); });
ot.Start();
p.WaitForExit();
ot.Join();
et.Join();
编辑:添加初始化StartInfo代码示例