references to Func's of different types

Question

I have a singleton that can register a func to resolve an id value for each type:

public void RegisterType<T>(Func<T, uint> func)

for example:

RegisterType<Post>(p => p.PostId );
RegisterType<Comment>(p => p.CommentId );

and then i want to resolve the id for an object, like these:

GetObjectId(myPost);

where GetObjectId definition is

public uint GetObjectId(object obj)

The question is, how can i store a reference for each func to invoke it lately. The problem is that each func has a different T type, and I can't do something like this:

private Dictionary<Type, Func<object, uint>> _typeMap;

How can resolve it? Expression trees?

regards Ezequiel

Answer 1

You don't need Expression Trees to do it the way you are suggesting, just need to nest the function when registering it.

public void RegisterType<T>(Func<T, uint> func){
             _typeMap.Add(typeof(T), obj=>func((T)obj));
}