Implementing multiparameter C++ template like behaviour on C# using Policy Pattern

Question

I\'m trying to implement a c++ like template with C# generics and policy pattern based on this answer

This is a sample of the pattern:

interface ISom         


        

Answer 1

Tried your code, but even simple calls did not work out of box. Main problem is that MyClass contains unknown element type 'myEement' - that type cannot be deduced from function call parameters. However - if you make a generalization and omit object type - your sample will work in out of box manner:

using System;
using System.Collections.Generic;

interface ISomePolicy 
{
    void _doSomething(U u);
}

public class MyClass :
     ISomePolicy,
     ISomePolicy
{
    internal object myEement { get; set; }

    public MyClass(object Element)
    {
        myEement = Element;
    }

    void ISomePolicy._doSomething(double u)
    {
        Console.WriteLine("this is double");
    }

    void ISomePolicy._doSomething(int u)
    {
        Console.WriteLine("this is int");
    }
}

static class MyClassExtension
{
    public static void doSomething(this P oTh, U u) where P : ISomePolicy
    {
        oTh._doSomething(u);
    }
}

class Program
{
    static void Main()
    {
        MyClass oClass = new MyClass(3);
        oClass.doSomething(0.5); //This works
        oClass.doSomething(1);   //This works            
        //oClass.doSomething("Will not work");
    }
}

What is up to myEement (or you probably meant myElement) - you can get's it's type at run-time if necessary.

myElement.GetType(), or cast to it - e.g.
if( myElement is int ) DoSomethingWithInt( (int) myElement );

However - reflection always might slow down your execution. If you don't intend to create super heavy class hierarchy with huge amount of instances - then this should be sufficient for your needs.