Call to DataMapper resolves to generic method - even when no generics are specified!!!

SonOfPirate posted on Tuesday, July 21, 2009

I have my own version of the DataMapper class that includes generic methods such as:

public static void Map<TSource, TTarget>(TSource source, TTarget target) { ... }

In my web page, I am using an CslaDataSource and handling the UpdateObject event.  I pass the e.Values property as the source to DataMapper.Map as follows:

DataMapper.Map(e.Value, myBO);

I would expect the call to resolve to the:

public static void Map(System.Collections.IDictionary source, System.Object target)

method but instead it goes to the generic method.  Any ideas why this would be the case?  I am not specifying the generic types in my call, so why would the compiler direct the call to the generic version?

 

RockfordLhotka replied on Tuesday, July 21, 2009

I would guess that the compiler is using type inference and is finding that the generic method is a closer match based on the parameter types. Perhaps the compiler team gave preference to generic matches over looser matches with the assumption you'd want strong typing when possible?