強調記載：Static Constructors (C# Programming Guide)

A static constructor is used to initialize any
static data, or to perform a particular action that needs performed once only. It is called automatically before the first instance is created or any static members are referenced.

 

class SimpleClass{    // Static constructor    static SimpleClass()    {        //...    }}

Static constructors have the following properties:

• A static constructor does not take access modifiers or have parameters.

• A static constructor is called automatically to initialize the
  class before the first instance is created or any static members are referenced.

• A static constructor cannot be called directly.

• The user has no control on when the static constructor is executed in the program.

• A typical use of static constructors is when the class is using a log file and the constructor is used to write entries to this file.

• Static constructors are also useful when creating wrapper classes for unmanaged code, when the constructor can call theLoadLibrary method.

Example

In this example, the class Bus has a static constructor and one static member,Drive(). When
Drive() is called, the static constructor is invoked to initialize the class.

 

public class Bus{    // Static constructor:    static Bus()    {        System.Console.WriteLine("The static constructor invoked.");    }    public static void Drive()    {        System.Console.WriteLine("The Drive method invoked.");    }}class TestBus{    static void Main()    {        Bus.Drive();    }}Output 
The static constructor invoked. 
The Drive method invoked. 
 
REF:
http://msdn.microsoft.com/en-us/library/k9x6w0hc(vs.80).aspx