using System;

​

class Program

{

    static void Main()

    {

        new DelegateTest<int>().InvokeDoSomething(1);

        new DelegateTest<string>().InvokeDoSomething("Hello");

    }

​

    delegate void DoSomethingDelegate<T>(T val);

​

    class DelegateTest<T>

    {

        public DelegateTest()

        {

            if (typeof(T) == typeof(int))

                _doSomething = (DoSomethingDelegate<T>)(Delegate)(DoSomethingDelegate<int>)DoSomethingInt;

            else if (typeof(T) == typeof(string))

                _doSomething = (DoSomethingDelegate<T>)(Delegate)(DoSomethingDelegate<string>)DoSomethingString;

            else throw new NotSupportedException();

        }

​

        DoSomethingDelegate<T> _doSomething;

​

        public void InvokeDoSomething(T x) => _doSomething(x);

​

        void DoSomethingInt(int val) => Console.WriteLine($"DoSomethingInt({val})");

        void DoSomethingString(string val) => Console.WriteLine($"DoSomethingString({val})");

    }

}

​