ansaurus

Question

Creating an instance of variable with reflection

Answer 1

+1 A:

Try this:

string s = (string)Activator.CreateInstance(t);

Activator.CreateInstance returns an instance boxed in an object so it must be cast to the correct type before you can use it.

In your example t is a Type object variable and not a type reference. You must either specify the type directly as in my example or you can use generics.

Rune Grimstad 2010-01-06 10:58:27

Answer 2

+4 A:

Yes. You have to convert to string, not to t. You may want a generic method, alternatively:

public T GetInstance<T>()
{
    Type t = typeof(T);
    T s = (T)Activator.CreateIstance(t);
    return s;
}

As things stand you are attempting to cast an object that is actually an instance of System.String to type System.Type...

David M 2010-01-06 10:58:59

You could just add a `where T : new()` contstraint on the method and the body would then be a single line: `return new T();`

LukeH 2010-01-06 11:03:26

Very true, and would be safer as types not implementing a paramaterless constructor could be picked up at compile time.

David M 2010-01-06 11:04:20

If I recall correctly there is a generic overload as well, so you should be able to do Activator.CreateInstance<T>();

Jaco Pretorius 2010-01-06 11:37:19

ansaurus

tags:

views:

answers:

Creating an instance of variable with reflection

related questions