Casting return value to a generic type

user_57334 0
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Suppose we have an interface with a single generic method:

public interface IExtender
{
    T GetValue<T>(string tag);
}

and a simple implementation A of it that returns instances of two different types (B and C) depending on the "tag" parameter:

public class A : IExtender
{
    public T GetValue<T>(string tag)
    {
        if (typeof(T) == typeof(B) && tag == null)
            return (T)(object) new B();
        if (typeof(T) == typeof(C) && tag == "foo")
            return (T)(object) new C();
        return default(T);
    }
}

is it possible to avoid the double cast (T)(object)? Or, is there a way to tell the compiler "hey, I am sure that this cast won't fail at runtime, just let me do it without first casting to object!"

generics c#
6 Answers

You can use dynamic to store your real result, but you have to be sure the generic argument type is the right type you return.

TResult GetResult<TResult>() 
{
    dynamic r = 10;
    return r;
}
user_45724700
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