Why isn't the static constructor of the parent class called when invoking a method on a nested class?

Question

Given the following code, why isn't the static constructor of "Outer" called after the first line of "Main"?

namespace StaticTester
{
    class Program
    {
        static void Main( string[] args )
        {
            Outer.Inner.Go();
            Console.WriteLine();

            Outer.Go();

            Console.ReadLine();
        }
    }

    public static partial class Outer
    {
        static Outer()
        {
            Console.Write( "In Outer's static constructor\n" );
        }

        public static void Go()
        {
            Console.Write( "Outer Go\n" );
        }

        public static class Inner
        {
            static Inner()
            {
                Console.Write( "In Inner's static constructor\n" );
            }

            public static void Go()
            {
                Console.Write( "Inner Go\n" );
            }
        }
    }
}

Answer 1

In the case of nested classes, if the nested class never refers to the static members of it's outer scope, the compiler (and CLR) are not required to call the static constructor of that outer class.

If you want to force the static constructor to run, just add code to the inner type that performs a read of a field or property of the outer type.

You can read more about the lazy initialization semantics of C# on Jon Skeet's blog - it's quite good. You could also check out his book - C# In Depth, it covers these topics as well ... in depth.