using System;

​

public class Program

{

    public static void Main()

    {

        ITypeStringFormattingService<Foo> formatter = new FooStringFormattingService();

        var foo = new Foo();

        string s = formatter.FormatValue(foo); // Will output "Foo title"

        Console.WriteLine(s);

        //But what I have is an unknown object:

        var unknownObject = ExternalObject.GetRandomObject();

        // This will error - how can I find the correct ITypeStringFormattingService?

        string friendlyString = formatter.FormatValue(unknownObject);

        Console.WriteLine(friendlyString);

    }

}

​

public interface ITypeStringFormattingService<in T>

{

    string FormatValue(T value);

}

​

public class FooStringFormattingService : ITypeStringFormattingService<Foo>

{

    public string FormatValue(Foo value)

    {

        return value.Title;

    }

}

​

public class Foo

{

    public string Title

    {

        get

        {

            return "Foo title";

        }

    }

}

​

public class Bar

{

    public string Name

    {

        get

        {

            return "Foo name";

        }

    }

}

​

public static class ExternalObject

{

    public static object GetRandomObject()

    {

        //This will come from an unknown source and won't be null

        return null;

    }

}