Question

I have two generic Interface

public interface IFunction<TParam, TResult>
{
    TResult Execute(TParam param);
}

public interface IFunctionService<TFunction, TParam, TResult>
    where TFunction : IFunction<TParam, TResult>
{
    IEnumerable<TResult> Execute(TParam param);

    void RegisterFunction(TFunction function);
}

If I want to use IFunctionService I have to write code like this:

IFunctionService<IFunction<string, bool>, string, bool> _Service;

As you can see I have to write TParam and TResult twice. And thats not very nice. Has anybody an idea how to make this nicer? I would like some code like this:

public interface IFunctionService<TFunction>
    where TFunction : IFunction<TParam, TResult>
{
    Type TParam = typeof(TFunction).GetGenericArguments()[0];
    Type TResult = typeof(TFunction).GetGenericArguments()[1];

    IEnumerable<TResult> Execute(TParam param);

    void RegisterFunction(TFunction function);
}

With typeof(TFunction).GetGenericArguments()[0] I would get the correct Type, but thats not possible in an Interface.

Any idea? Do you need to know anything else?

Thanks in advance! Lukas

Answer 1

Is the TFunction type really necessary in your IFunctionService interface declaration?
Could you refactor it to something like this?

public interface IFunctionService<TParam, TResult>{
    IEnumerable<TResult> Execute(TParam param);

    void RegisterFunction(IFunction<TParam, TResult> function);
}