Is this a good way to implement an asynchronous programming model?

Question

Recently, I am torn, trying to find out everything I can about .Net multithreading. (Improve yourself, but still feel that there is something to learn). Now I focus on APM (asynchronous programming model), which is commonly known as:

//non async method
public int DoSomeWork(int arg)
{
   //do something and return result
}

//async version
public IAsyncResult BeginDoSomeWork(int arg, AsyncCallback callback, object @object)
{

}

public int EndDoSomeWork(IAsyncResult result)
{

}

Now let's say that I'm writing some kind of library, and I want to disclose this function to everyone who uses my API, I was thinking about ways to implement this template. Implementing the IAsyncResult interface is an option, but it seems rather complicated. My question is that using a delegate is an acceptable solution. I mean the following:

public class MyClass
{
    private Func<int, int> func;

    //non async method
    public int DoSomeWork(int arg)
    {
        //do something and return result
    }

    //async version
    public IAsyncResult BeginDoSomeWork(int arg, AsyncCallback callback, object @object)
    {
        this.func = new Func<int, int>(DoSomeWork);
        var asyncResult = this.func.BeginInvoke(arg,callback,object);
        return asyncResult;
    }

    public int EndDoSomeWork(IAsyncResult result)
    {
        return this.func.EndInvoke(result);
    }
}

, BeginXxx EndXxx, . IAsyncResult, - , .

Answer 1

, APM, .

?

, , , :

MyClass c = new MyClass();
Func<int, int> f = c.DoSomeWork;
IAsyncResult ar1 = f.BeginInvoke(1, null, null);
IAsyncResult ar2 = f.BeginInvoke(2, null, null);
//...

, , APM , , , APM, .

Answer 2

IMHO, , async , , .

Answer 3

, , . . , .

, SO Linq. , . .

. . , , :

public delegate void delVoidMethod(params object[] args);

/// <summary>
/// Publishes an asynchronous method to the delegate collection.
/// </summary>
/// <param name="methodOwner">Target object owning the delegated method.</param>
/// <param name="method">The delegated method.</param>
/// <param name="callback">The method designated as a callback delegate.</param>
/// <param name="ptr">The delegated method runtime handle.</param>
/// <returns>True if publishing was successful.</returns>
public bool PublishAsyncMethod(object target , MethodInfo method ,
    MethodInfo callback , out IntPtr ptr)
{
    try
    {
        ptr = method.MethodHandle.Value;

        delVoidMethod dMethod = (delVoidMethod)Delegate.CreateDelegate
            (typeof(delVoidMethod) , target , method);
        AsyncCallback callBack = (AsyncCallback)Delegate.CreateDelegate
             (typeof(AsyncCallback) , target , callback);

        handlers[ptr] = new DelegateStruct(dMethod , callBack);

        Logger.WriteLine("Delegate : {0}.{1} -> {2}.{3} published." ,
            method.DeclaringType.Name , method.Name ,
            callback.DeclaringType.Name , callback.Name);
        return true;
    }
    catch (ArgumentException ArgEx)
    {
        Logger.Write(DH_ERROR , ERR_MSG ,
            ArgEx.Source , ArgEx.InnerException , ArgEx.Message);
    }
    catch (MissingMethodException BadMethEx)
    {
        Logger.Write(DH_ERROR , ERR_MSG ,
            BadMethEx.Source , BadMethEx.InnerException , BadMethEx.Message);
    }
    catch (MethodAccessException MethAccEx)
    {
        Logger.Write(DH_ERROR , ERR_MSG ,
            MethAccEx.Source , MethAccEx.InnerException , MethAccEx.Message);
    }

    ptr = IntPtr.Zero;

    return false;
}

Answer 4

, .

Facade pattern, . , ( ) , AsyncCallback IAsyncResult, , .

Answer 5

I personally prefer to use the event to notify the completion of the asynchronous process, if the class is intended to be used by another library, using the AsyncOperation class and the SendOrPostCallback delegate to make sure that events are raised in the caller stream so as not to violate the user interface. If, however, the asynchronous operation is to be performed in the same assembly, I prefer the calling code to determine how to make the asynchronous call.