When you override a virtual method in C# you are required to ensure that the stated accessibility of the overridden method - that is, whether it is public, internal, protected or protected internal(*) – is exactly re-stated in the overriding method. Except in one case. I refer you to section 10.6.4 of...

Reader Jesse McGrew asks an excellent follow-up question to my 2005 post about why you cannot access a protected member from a derived class . (You probably want to re-read that post in order to make sense of this one.) I want to be clear in my terminology, so I’m going to define some terms. Suppose...

I asked a second follow-up question back in Part Two: Suppose you wanted to make this hierarchy an immutable collection, where "Add" and "Remove" returned new collections rather than mutating the existing collection. How would you represent the parenting relationship? The short answer is "I wouldn't...

In Part Two I asked a couple of follow-up questions, the first of which was: Suppose you were a hostile third party and you wanted to mess up the parenting invariant. Clearly, if you are sufficiently trusted, you can always use private reflection or unsafe code to muck around with the state directly...

Holy goodness, I've been busy. The MVP Summit was fabulous for us; thanks to all who attended and gave us great feedback on our ideas for evolving the languages and tools. And I've been doing some longer-lead thinking and working on language futures, which I will blog about at a later date. Last time...

This is a follow-up to my 2005 post on the same subject which I believe sets a personal record for the longest time between parts of a series. (Of course, I didn't know it was a series when I started it.) Please read the previous article in this series, as this post assumes knowledge of part one. .....

A question I got recently was about access to protected methods from a derived class. Clearly that's what "protected" means – that you can access it from a derived class. In that case, why doesn't this work? class Ungulate { protected void Eat() { /* whatever */ } } class Giraffe : Ungulate { public...