MyObject obj1 = obj as MyObject;

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);
}
}

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yguyon28Asked:
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käµfm³d 👽Commented:
It's a cast. Ordinarily, you use parentheses and a type name to perform a cast:

e.g.

MyObject obj1 = (MyObject)obj;

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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
}

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