How do I enumerate an enum?

How can you enumerate an enum in C#? E.g. the following code does not compile:

public enum Suit {
    Spades,
    Hearts,
    Clubs,
    Diamonds
}

public void EnumerateAllSuitsDemoMethod() {
    foreach (Suit suit in Suit) {
        DoSomething(suit);
    }
}

And gives the compile time error:

'Suit' is a 'type' but is used like a 'variable'

It fails on the Suit keyword, the second one.