The following kinds of parameters are available:

private static void Swap(ref int x, ref int y)
{
    int temp = x;
    x = y;
    y = temp;
}
...
i = 42;
j = 27;
Swap(ref i, ref j);
// i has the value 27
// j has the value 42

• As in C++, in C# a method is statically bound to its class unless the keyword virtual appears in the declaration of the method.
• If a subclass wishes to override a method declared as virtual in a superclass, the keyword override must appear in the method's declaration in the subclass.
• If a subclass does not wish to override but instead wishes to provide its own method as well, the keyword new must appear in the method's declaration in the subclass.