How can I initialize a global nested Dictionary globally?

Question

I have my Dictionary declared like this:

private static Dictionary<string, Dictionary<string, string>> myDictionary;

I want to initialize it globally. The closest I have come initializes the outer Dictionary, but still leaves me with a null reference to the inner Dictionary:

private static Dictionary<string, Dictionary<string, string>> myDictionary
 = new Dictionary<string, Dictionary<string, string>>();

I need to avoid initializing it in a method, because I don't want to force the user to call a method before being able to use my class. The user only has access to static methods. I could create a singleton when they call one of the methods, but that's dirty.

How can I declare both dictionaries globally? Something along the lines of one of these (although neither compile):

private static Dictionary<string, Dictionary<string, string>> myDictionary
 = new Dictionary<string, new Dictionary<string, string>>();

or

private static Dictionary<string, string> inner = new Dictionary<string, string>();
private static Dictionary<string, Dictionary<string, string>> myDictionary
 = new Dictionary<string, inner>();

Answer 1

Use the static constructor like this (assuming that the myDictionary variable is in a class called MyClass) :

public class MyClass
{
    private static Dictionary<string, Dictionary<string, string>> myDictionary;

    static MyClass()
    {
        //Initialize static members here
        myDictionary = new Dictionary<string, Dictionary<string, string>>();
        myDictionary.Add("mykey", new Dictionary<string, string>());
        ...
    }
}

The framework will make sure that the static constructor is automatically executed before you access any member of the class.