Is this code actually multithreaded?

Question

Goal: Spin up 20 threads that will all hit the SessionFactory.GetSessionFactory(key) method at the same time for testing purposes. (I'm trying to simulate a multi-threaded environment such as ASP.NET)

Question: By using the EndInvoke() method am I essentially calling the GetSessionFactory(key) method synchronously or is my code correct in simulating multiple threads all hitting GetSessionFactory(key) at the same time?

Thanks,

Kyle

public void StressGetSessionFactory()
{
    for (int i = 0; i < 20; i++)
    {
        Func<string, ISessionFactory> method = GetSessionFactory;
        IAsyncResult asyncResult = method.BeginInvoke("RBDB", null, null);
        ISessionFactory sessionFactory = method.EndInvoke(asyncResult); //My concern is with this call

        Debug.WriteLine("RBDB ISessionFactory ID: " + sessionFactory.GetHashCode());
    }

}

static ISessionFactory GetSessionFactory(string key)
{
    return SessionFactory.GetSessionFactory(key);
}

Answer 1

IAsyncResult asyncResult = method.BeginInvoke("RBDB", null, null);
ISessionFactory sessionFactory = method.EndInvoke(asyncResult);

It's not parallel, from MSDN:

The EndInvoke method is used to retrieve the results of the asynchronous call. It can be called any time after BeginInvoke; if the asynchronous call has not completed, EndInvoke will block until it completes.

To make parallel calls you could use a higher level abstraction (like the TPL i.e. would give you all of this almost for free) or slightly refactor your code - make the asynchronous calls first, then collect the results afterwards (untested):

IAsyncResult[] asyncResult = new IAsyncResult[20];
ISessionFactory[] sessionFactories = new ISessionFactory[20];
Func<string, ISessionFactory> method = GetSessionFactory;
for (int i = 0; i < 20; i++)
{
    asyncResult[i] = method.BeginInvoke("RBDB", null, null);
}
for(int i = 0; i < 20; i++)
{
    sessionFactories[i] = method.EndInvoke(asyncResult[i]); 
}

Note that with BeginInvoke() you do not have a guarantee that you are in fact making 20 calls in parallel, since it uses the thread pool it will parallelize as it sees fit.