casting vs using the 'as' keyword in the CLR
- by Frank V
I'm learning about design patterns and because of that I've ended using a lot of interfaces. One of my "goals" is to program to an interface, not an implementation.
What I've found is that I'm doing a lot of casting or object type conversion. What I'd like to know is if there is a difference between these two methods of conversion:
public interface IMyInterface
{
void AMethod();
}
public class MyClass : IMyInterface
{
public void AMethod()
{
//Do work
}
// other helper methods....
}
public class Implementation
{
IMyInterface _MyObj;
MyClass _myCls1;
MyClass _myCls2;
public Implementation()
{
_MyObj = new MyClass();
// What is the difference here:
_myCls1 = (MyClass)_MyObj;
_myCls2 = (_MyObj as MyClass);
}
}
If there is a difference, is there a cost difference or how does this affect my program?
Hopefully this makes sense. Sorry for the bad example; it is all I could think of...
Update: What is "in general" the preferred method? (I had a question similar to this posted in the 'answers'. I moved it up here at the suggestion of Michael Haren. Also, I want to thank everyone who's provided insight and perspective on my question.
