Getting the thread ID from a thread

In C# when debugging threads for example, you can see each thread's ID.

I couldn't find a way to get that same thread, programmatically. I could not even get the ID of the current thread (in the properties of the Thread.currentThread).

So, I wonder how does Visual Studio get the IDs of the threads, and is there a way to get the handle of the thread with id 2345, for example?

GetThreadId returns the ID of a given native thread. There are ways to make it work with managed threads, I'm sure, all you need to find is the thread handle and pass it to that function.

GetCurrentThreadId returns the ID of the current thread.

GetCurrentThreadId has been deprecated as of .NET 2.0: the recommended way is the Thread.CurrentThread.ManagedThreadId property.

In C# when debugging threads for example, you can see each thread's ID.

This will be the Ids of the managed threads. ManagedThreadId is a member of Thread so you can get the Id from any Thread object. This will get you the current ManagedThreadID:

Thread.CurrentThread.ManagedThreadId

To get an OS thread by its OS thread ID (not ManagedThreadID), you can try a bit of linq.

int unmanagedId = 2345;
ProcessThread myThread = (from ProcessThread entry in Process.GetCurrentProcess().Threads
   where entry.Id == unmanagedId 
   select entry).First();

It seems there is no way to enumerate the managed threads and no relation between ProcessThread and Thread, so getting a managed thread by its Id is a tough one.

For more details on Managed vs Unmanaged threading, see this MSDN article.