How to debug a single thread in Visual Studio?

c# asp.net multithreading visual-studio-2010 breakpoints
Xaqron picture Xaqron · Mar 14, 2011 · Viewed 91.9k times · Source

I have a solution with some projects. There are several break-points in different projects. I want to trace the first thread hit one of these break-points and continue tracing that single thread despite of other threads entering the same code-blocks.

I know this is possible through defining a condition on the break-point, that is, thread name = ... or thread Id = ... but my case is a heavy loaded ASP.NET application and as soon as I attach to w3wp.exe many threads will hit the break-points. I need some thing like a ThreadLocal<break-point>.

Is it possible? If so, how?

Answer

Matt Faus picture Matt Faus · Jun 28, 2011

Here's what I did:

  1. Set a conditional break point that I knew would only hit on the thread that I was looking for.

  2. Once the breakpoint hits and you are in the thread you want, in the Visual Studio Threads window (while debugging, Debug -> Windows -> Threads), Ctrl + A (to select all threads), and then Ctrl + click the thread you are currently on. You should have all threads except the one you want to debug selected.

  3. Right-click, and choose "Freeze".

Now, Visual Studio will only step through the thawed thread. It seems to be much slower when doing this, presumably because it has to loop through all of the frozen threads, but it brought some sanity to my multi-threaded debugging.

Related questions

"Context cannot be used while the model is being created" exception with ASP.NET Identity

Why is this happening when we make a call to the AccountApiController.Register() method? what is trying to use the context? what is trying to create the context? how do we avoid this? how do we debug this? "Message":"An …

Read More
Calling async methods from non-async code

I'm in the process of updating a library that has an API surface that was built in .NET 3.5. As a result, all methods are synchronous. I can't change the API (i.e., convert return values to Task) because that would …

Read More
ASP.NET Multithreading Web Requests

I'm building a page in my ASP.NET solution that retrieves most of its data from a 3rd Party API Service. The page itself will need to make approximately 5 individual different calls to the API to populate all of its …

Read More