MyObject obj1 = obj as MyObject;

yguyon28
yguyon28 used Ask the Experts™
on
Can someone tell me what this line of code mean.... MyObject obj1 = obj as MyObject;

class MyObject : IComparable
{
public int ID{ get; set; }
public int CompareTo(object obj)
{
MyObject obj1 = obj as MyObject;
return this.ID.CompareTo(obj1.ID);
}
}

Open in new window

Comment
Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
Glanced up at my screen and thought I had coded the Matrix...  Turns out, I just fell asleep on the keyboard.
Most Valuable Expert 2011
Top Expert 2015
Commented:
It's a cast. Ordinarily, you use parentheses and a type name to perform a cast:

e.g.

MyObject obj1 = (MyObject)obj;

Open in new window


This has the consequence that if obj is not actually of type MyObject, or descended from it, then you will encounter an exception. The as operator also performs casts, but it has the added benefit that if the cast will not succeed--that is, if the thing being cast isn't of the type being cast to (or descended from it)--then as will return null. It's a good way to confirm a cast will succeed before working with the casted reference.

A word of warning:  Since as can return null you should be checking for null any time you use as:

e.g.

MyObject obj1 = obj as MyObject;

if (obj1 != null)
{
    // Cast succeeded
}

if (obj1 == null)
{
    // Cast failed
}

Open in new window

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial