Static Constructor

I was asked this item in a job interview. So write here to note ourself.

Static Constructor  can be also called as Class constuctor. Its usage is initial static field.

following is the limit of Static constructor :

1.just static field can be invoke in this function;

2.it just can be called only once;(at the first object of the class initialed)

3.it can't have any parameters;

4.it must be a private function;

5.it can't invoke any other constructors.

When and where should it be used?