A type (class, interface, or value type) can contain a special method called a type initializer, which is used to initialize the type itself. This method shall be static, take no parameters, return no value, be marked with rtspecialname and specialname (§II.15.4.2.6), and be named .cctor.
Like instance constructors, type initializers can write into static fields of their type that are marked with the initonly attribute (§II.16.1.2).
[Example: The following shows the definition of a type initializer:
.class public EngineeringData extends [mscorlib]System.Object
{
.field private static initonly float64[] coefficient
.method private specialname rtspecialname static void .cctor() cil managed
{
.maxstack 1
// allocate array of 4 Double
ldc.i4.4
newarr [mscorlib]System.Double
// point initonly field to new array
stsfld float64[] EngineeringData::coefficient
// code to initialize array elements goes here
ret
}
}
end example]
[Note: Type initializers are often simple methods that initialize the type's static fields from stored constants or via simple computations. There are, however, no limitations on what code is permitted in a type initializer. end note]