using System;

using System.Threading.Tasks;

using System.Collections.Generic;

var store = new FuncStore<DefaultParameters>();

var lambda01 = (DefaultParameters parameters) => {

    var str = parameters.SomeProperty + "01"; // Whatever

    return Task.FromResult<dynamic>(str); // Simulate async op

};

var lambda02 = (DefaultParameters parameters) => {

    var number = Convert.ToInt32(parameters.SomeProperty) + 2; // Whatever

    return Task.FromResult<dynamic>(number); // Simulate async op

};

​

// These both lambdas differ on their return type

// one is Task<string> and the other is Task<int>

store.AddFunc("01", lambda01);

store.AddFunc("02", lambda02);

​

// Many other lambdas and additions later...

var parameters = new DefaultParameters();

await store.ExecuteAllAsync(parameters);

​

public class DefaultParameters {

    public string SomeProperty { get; set; }

}

​

public class FuncStore<TParameters> {

    private readonly Dictionary<string, dynamic> _funcCache = new();

    public void AddFunc(string key, Func<TParameters, Task<dynamic>> value) {

        _funcCache.Add(key, value);

    }

    public async Task ExecuteAllAsync(TParameters parameters) {     

        foreach(var (_, func) in _funcCache) {

            // Problem here. How do I invoke each lambda?

            // Attempt 1:

            var typedFunc = func as Func<TParameters, Task<dynamic>>; // NullReferenceExeption, the cast fails

            var result = await typedFunc(parameters);

            Console.WriteLine(result);

            // Attempt 2:

            //var asDelegate = func as Delegate;

            //var task = (Task)asDelegate.DynamicInvoke(new object[]{ parameters });            

            //Console.WriteLine(await task);

        }

        await Task<int>.FromResult(0);

    }

}