System.Threading.Thread inheritance

Question

Is it possible to inherit from the Thread class and override the Start method?

Answer 1

using System.Threading;

namespace NGrubb.Threading {

    public abstract class BaseThread {
        private Thread m_thread;

        public BaseThread() {
            m_thread = new Thread( Run );
        }

        public void Start() {
            m_thread.Start();
        }

        protected abstract void Run();
    }
}

Answer 2

Regarding why someone would want to do this: a lot of languages (e.g. Java) and/or thread APIs (e.g. Qt) allow developers to implement threads by inheriting from a "thread" base class, and then overloading a method that implements the thread routine.

Having used this model extensively in Qt, I actually find it very handy--instead of having threads target some function or method, which often leads to weird and/or convoluted code, the whole thread is contained inside of an object.

Here's example code using the Qt API:

class MyThread : public QThread
{
    Q_OBJECT

protected:
    void run();
};

void MyThread::run()
{
    ...something I need threaded...
}

QThread is Qt's threading base class. To use MyThread, create an instance of the thread object and call QThread::start(). The code that appears in the run() reimplementation will then be executed in a separate thread.

What's nice about this is I think it lets you really contain everything a thread needs inside a single object, and (in my experience), it makes for a very coherent object model. I don't think it meets everyone's needs, but I was a bit surprised that C# doesn't have such a basic threading model to be honest.

I definitely don't buy that C#'s Thread class is sealed because of kernel complexity; if Qt can supply a cross-platform threading library that allows inheritance of QThread, I see no real reason MSFT couldn't provide the same capability in a threading class in C#.