using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var repository = new Repository();

        repository.Store<Foo>(xs => xs.Count());

​

        int Compute<M>(string[] source) => repository.Fetch<M>().Invoke(source);

​

        // Call Compute<M>

        var runtimeKnownTime = typeof(Foo);

        var computeResult = InvokeHelper(Compute<object>, new[] { "A", "B" }, runtimeKnownTime);

​

        Console.WriteLine(computeResult);

    }

    // This code was created by Jon Skeet : https://stackoverflow.com/a/43349127/2729609

    // I only changed Action<int> to Func<int, int> and changed the return type.

    private static int InvokeHelper(Func<string[], int> int32Func, object data, Type type)

    {

        // You probably want to validate that it really is a generic method...

        var method = int32Func.Method;

        var genericMethod = method.GetGenericMethodDefinition();

        var concreteMethod = genericMethod.MakeGenericMethod(type);

        return (int)concreteMethod.Invoke(int32Func.Target, new[] { data });

    }

}

​

public class Foo { }

​

public class Repository

{

    private Dictionary<Type, object> _store = new Dictionary<Type, object>();

​

    public void Store<T>(Func<string[], int> value)

    {

        _store[typeof(T)] = value;

    }

​

    public Func<string[], int> Fetch<T>()

    {

        return (Func<string[], int>)_store[typeof(T)];

    }

}