Debug.WriteLine not working

Question

In the past, perhaps versions of Visual Studio prior to the 2008 that I am using now, I would do something like this in my VB.NET code:

System.Diagnostics.Debug.WriteLine("Message")

..and the output would go to the output window.

Now it doesn't. Something must first apparently be enabled.

If this involves "attaching a debugger", please explain how to do it. It seems to me that it should just work without too much of a fuss.

Here's a video explaining the issue in real time and showing you all my settings

http://screencast.com/t/YQnPb0mJcs

I'm using VS2008

Answer 1

It should go to the output window if your app is compiled with the Debug configuration rather than the Release configuration. But instead of Debug.WriteLine(), try using Trace.WriteLine() (optionally with a ConsoleTraceListener attached).

Answer 2

Check your Immediate Window, you might have all the output redirected to it

Answer 3

Check to see if the "Redirect all Output Window text to the Immediate Window" is checked under Tools -> Options -> Debugging -> General.

Alternatively, you can use the Console.WriteLine() function as well.

Answer 4

Do you definitely have the DEBUG constant defined? Check under project properties > Compile > Advanced Compile Options (there's a checkbox for the DEBUG constant, if it isn't checked your Debug.XXX statements will not be executed).

Answer 5

Some extra ideas to try or check:

• Put a breakpoint before Debug.WriteLine and see what's in System.Diagnostics.Trace.Listeners collection. You should see DefaultTraceListener. If you don't see anything, then no one is listening and that's problem.
• Is it possible that the trace listeners being cleared/modified somewhere such as in config file or in the code?
• Have you installed any package or add-in to Visual Studio? or using a third-party library?
• Can you see debug messages outside of VS? There is a SysInternals application called DebugView that monitors and shows debug output in your system. Run that tool and then run your application. You should see your debug message in DebugView. At least you will know that your application is outputting debug messages but VS does not seem to be listening.
• Have you gone through the contents of the output window to see if there is any exception or error being reported. Your debug output is not there but there might be somethings in there that can provide some clues.

Answer 6

Right-click in the output window, and ensure "Program output" is checked.

Answer 7

Do visual studio running "debugging" (F5) when you trying to see the output?

In order that Visual Studio will output the message, and must listen to the DefaultTraceListener. Make sure that the debugger is running.