How to asynchronously read the standard output stream and standard error stream at once

I want to read the ouput of a process in the form as is in a console (standard output is blended with standard error in one stream). Is there a way how to do it?

I was thinking about using

ProcessStartInfo.UseShellExecute = true;

but then I cannot read asynchronously the output. If I set

process.ProcessStartInfo.UseShellExecute = false;  
process.StartInfo.RedirectStandardOutput = true;
process.OutputDataReceived += new DataReceivedEventHandler(partialOutputHandler);

then I can read standard output (I can do the same for standard error) but I don't know how to simulate the behavior of console (the blending of stdout and stderr).

This is similar to Linux which has the feature of redirecting standard error stream to the standard output stream; how?

Solution

I found the answer:

The output streams are buffered. There is no way to get the true sequential order of the items inserted into the streams. In fact it makes little sense as both streams can be written too at the same time. They are independent of each other. Therefore the best you can do is get the sequential output from each one as they arrive.

Generally this is not an issue though as almost all console apps use standard output for both output and error messages. The error stream is used by some apps but the messages are generally duplicates of the errors generated in the output stream.

Source: http://social.msdn.microsoft.com/Forums/uk/csharpgeneral/thread/192b6df7-9437-42cf-81c1-c125021735ba