Create fake object by interface

Question

I need to dynamically create fake object by interface. Every method and property of this fake object should just throw NotImplementedException. Is there any simple way how to do it only with .NET reflection API?

Answer 1

You could use a mocking API such as Moq. It's designed for mocking in unit tests, but it should do what you need.

Answer 2

Maybe ImpromptuInterface can help.

A sample code (copied from its homepage) is:

    using ImpromptuInterface;
    using ImpromptuInterface.Dynamic;

    public interface IMyInterface{

       string Prop1 { get;  }

        long Prop2 { get; }

        Guid Prop3 { get; }

        bool Meth1(int x);
   }

   //Anonymous Class
    var anon = new {
             Prop1 = "Test",
             Prop2 = 42L,
             Prop3 = Guid.NewGuid(),
             Meth1 = Return<bool>.Arguments<int>(it => it > 5)
    }

    IMyInterface myInterface = anon.ActLike<IMyInterface>();

Answer 3

Castle Proxies is a neat library that generates proxy objects for interfaces at run time. All the major mocking frameworks use Castle Proxies under the hood too.

The learning curve is steeper than using something like Moq, but it may be a more appropriate fit for your needs as Moq is designed to be used specifically for unit testing so the API may be too 'noisy' for what you're after.