带锁的 C# 线程池

Question

I'm really new to C# and am keen to learn the most effective way and utility classes to help with handling threads.

What I'm trying to do is to manage a queue of jobs. Each job has a group that it applies to. Jobs can run in parallel, but only one job per grouping. In a set of 1000 jobs to process, there may be 100 different groupings.

In Pseudo code it would be:

    var job = Jobs.First(job.GroupNotExecuting);
    job.RunSynchronously();

Where job.GroupNotExecuting checks to see if there is an available lock for that group.

What would be the best way to implement this in C#?

As mentioned, I'm new to C#, so just want to get the best habit in place for a scenario like this. Assistance would be appreciated!

(In case it matters, I'm working in Visual Studio 2013, .NET Framework 4.5)

Answer 1

You can try using a boolean in each class as a "isBusy" flag. When the job starts it sets the "isBusy" to true then does whatever it is supposed to do. But right before the job completes it sets the "isBusy" to false.

For the calling code, it just needs to check that "isBusy" boolean. If it's true, then the job is still running. If its false, then the job is done, or has yet to be run.

Or, make use of the System.Threading namespace. Those give you an event that can be called when the backgroundworker completes.

Answer 2

In the end I have used the SemaphorSlim class to handle the updates.

To each job I added the process of obtaining a Semaphore from a shared / static list and waiting for it to be available. This way they could be added into the same joint pool and be processed as they became available.

The downside, is that in theory a thread could be waiting for another one to process, where it may otherwise have been able to look for another job to handle in the meantime.