Question

I have an input string such as

"x=y|a=b|c=10" etc

which gets converted to dynamic which i use as

dynamic d = getDynamicFromStringAbove();

someFunc( d.a.AsType<int>() )

where AsType is an extension method defined as

   public static T AsType<T>(this string o){
        return (T) Convert.ChangeType(o, typeof(T));
    }   

QUESTION – Is there anything in the framework which provides this already

        object.AsType<T>()

?? It seems pretty handy with dynamic types so i am guessing it’s there and i don’t want to add code which already exists

Answer 1

No, there’s no built-in method that works like your extension method. I think the framework designers wanted people to know that an explicit operation has to be performed to parse a string to an int, etc.

BTW, might I suggest changing your AsType method to use a TypeConverter instead of Convert.ChangeType? It’s a little more powerful and flexible. For example, it works better for converting enum values to their respective types.

public enum Foo {A,B,C}
...

TypeDescriptor.GetConverter(typeof(Foo)).ConvertFrom("A"); // Yields Foo.A
Convert.ChangeType("A", typeof(Foo));                      // Throws exception

See this answer for more info.

Update

I should point out:

1. This approach really only makes sense if your .AsType() method takes an object as its parameter. As it stands in the question you are taking a string, and in what way is s.AsType<int>() preferable to int.Parse(s)?
2. Since you cannot use extension method syntax on a dynamic value, the code provided in the question won’t actually work without casting d.a to a string value.