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Jon Skeet
If a derived class' "reference" goes out of scope but the base class reference stays, does the derived object ever change?
(In C# 5.0) It's a pretty simple yes/no question which I can't seem to find an explicit answer for which probably means I'm looking in the wrong place or using the wrong terms in searching for the answer.
If I create a derived class object, then I cast it to a base class and the original reference goes out of scope, does the reference held in the base class casting preserve the entire derived class object? I.E. can I later recast it as the derived class with the original object always still intact?
It's a reference to the same object. The compile-time type of the expression which has a value of that reference is irrelevant. It's important to understand that there really is only one object - it's not like there's a base class object and then an associated derived class object.
That's why you can downcast as well:
string x = "hello";
object y = x;
string z = (string) y;
All three variables have the same value - they're all references to the same object. No information is lost. The reference itself is just "a way of getting to an object" - the variable determines which references are valid, and informs the compiler about which members can be accessed via that variable, but it doesn't change the value itself.
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