How To Write To Console From Background Thread's Event Loop?

Question

Is it possible to write error messages to the console from process that has been fired up? Normally we are used to using Console.Writeline() from within the console. The additional process (in another assembly) is designed to be operated by the console, and potentially also through a GUI.

However if we attach methods to event handlers (i.e. a callback), then Console.WriteLine is not working.

Currently using:

var thread=new Thread(someMethod);
thread.Start();

Subsequently, callbacks may get fired off, it's here that console messages go missing.

It should still work using `Console.WriteLine()`. Are you getting an error? — Neil Knight, Jan 31 '12 at 14:44

score 2 · Accepted Answer · edited May 23 '17 at 11:58

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Console.WriteLine() should work as well.

Update:

If you want to capture output of some console application, please take a look at Capturing console output from a .NET application (C#).

edited May 23 '17 at 11:58

Community

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answered Jan 31 '12 at 14:46

Sergey Vyacheslavovich Brunov

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+1: Useful info. Not another console app though. Just another internal thread. – sgtz Feb 01 '12 at 17:35

score 2 · Answer 2 · answered Jan 31 '12 at 14:48

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If you're concerned about two streams of messages co-mingling, why not use Console.Error.WriteLine()? You can then redirect the error stream at execution to (for example) a file.

answered Jan 31 '12 at 14:48

Randolpho

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+1: ty. don't mind if two streams co-mingle. Just concerned that one stream is not showing up at all. Just want to see the info pop up in the console during execution right now. I've updated the question. – sgtz Feb 01 '12 at 17:41

score 1 · Answer 3 · answered Jan 31 '12 at 14:48

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I'm not quite sure if I understand this correctly. Do you want to read from the standard output of a child process and write in the parent's console? Then you can use the Process.StandardOutput property to get a StreamReader and start reading.

answered Jan 31 '12 at 14:48

Tudor

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It's a .net assembly that uses a 3rd party assembly. I'm wondering if the 3rd party .dll is sucking in console console data on the callback events. Is that possible? I updated the question. – sgtz Feb 01 '12 at 17:34

score 1 · Answer 4 · edited May 23 '17 at 11:44

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If you use the standard .NET tracing, you could configure a ConsoleTraceListener through the app.config: http://msdn.microsoft.com/en-us/library/system.diagnostics.consoletracelistener.aspx

This approach is explored more through this question: Redirect Trace output to Console

It's quite nice for diagnostic purposes as you mention. You can hook up text file writers, etc.

edited May 23 '17 at 11:44

Community

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answered Jan 31 '12 at 14:48

jglouie

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+1: ty. that's really handy info. Problem is that even Console.WriteLine is failing. I've updated the question a little. – sgtz Feb 01 '12 at 17:39

score 1 · Answer 5 · answered Jan 31 '12 at 14:52

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Is this an external, compiled process, i.e. an executable?

If you're using the Process class to start the process, you might be looking for the Process.StandardOutput property, which will let you redirect the text normally written to the console to another stream.

Otherwise, can you clarify what kind of "process" you're talking about?

answered Jan 31 '12 at 14:52

qxn

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It's not an external compiled process. That's useful to know though. – sgtz Feb 01 '12 at 17:44

How To Write To Console From Background Thread's Event Loop?

5 Answers5