Question

I currently have method which is trying to find out what the obj is it recieved. It knows is on a certain interface, for example IService but I have code which looks at it and tries to tell me is it is for example Service1 or Service2.
I currently a lot of if(obj is thisObj) style statements, what would be the best solution to make this code pretty?

here is a sample of what exactly I have:

    public void DoSomething(IService service)
    {
        if (service is Service1)
        {
            //DO something
        }

        if (service is Service2)
        {
            //DO something else
        }           
    }

now having two isnt too much of a bad thing, but I am looking at having probably 20+ of these which just becomes awful to use.

Any ideas?

---

ok further details I think are needed and here they are:

prior to this method I have another method which is recieving a xml doc, which it them deserializes into the interface IService, so we have something like this:

    private static void Method(InnerXml)

    {

            var messageObj = (IServiceTask)XmlSerialization.Deserialize(typeof(IServiceTask), InnerXml);

            var service = GetService(messageObj);
            service.PerformTask(xmlDoc);

    }

    private static IService GetService(IServiceTask messageObj)
    {
        var service = new IService ();

        if (messageObj is Task1)
        {
            service = (SomeService)messageObj;
        }

        if (messageObj is Task2)
        {
            service = (SomeOtherService)messageObj;
        }
        return service ;
    }

Hopefully that makes it a bit clearer.

Answer 1

What I believe you want is:

class ServiceFactory 
{
     Dictionary<Type, NewService> serviceCreators;
     ServiceFactory() 
     {
         serviceCreators = new Dictionary<Type, NewService>();
         serviceCreators.Add(typeof(Task1), delegate { return new SomeService(); });
         serviceCreators.Add(typeof(Task2), delegate { return new SomeOtherService(); });
     }

     public IService CreateService(IServiceTask messageObj) 
     {
         if(serviceCreators.Contains(messageObj.GetType()) 
         {
              return serviceCreators[messageObj.GetType()];
         }
         return new DefaultService();
     }
}

delegate IService NewService();

Or maybe to add a new method to IServiceTask – CreateService.