C # Programming (24)----------modifiers

Modifier

Modifiers are keywords that apply to types or members . Modifiers can specify the visibility of a method , such as public or private, and you can specify the nature of an item , such as a vritual or abstract that has just been sent.

Modifiers for visibility

Modifier	Applied to	Description
Public	All types or members	Any code can access the item
Protected	All members of type and inline type	Only derived types can access the item
Internal	All types or members	The item can only be accessed in the assembly that contains it
Private	All members of type and inline type	The item can only be accessed in the type to which it belongs
protected internal	All members of type and inline type	The item can only be accessed in any code that contains his assembly and derived types

Note that the definition of a class can only be internal or public , depending on whether you want to access it outside of the assembly that the type contains :

public class MyClass

{}

The type cannot be declared asProtected,private,Andprotected internal, Because these modifiers have no meaning for the types contained in the namespace . So these modifiers can only be applied with members . But , You can use these modifiers to define nested types (, contains types because in this case , Type also has member status . So the following code is legal :

public class Outerclass

{

Protected class Innerclass

{}

}

If there is a nested type , the internal type always has access to all members of the external type . So , in the code above,the code in Innerclass can access all members of the Outerclass , and even the private members of Outerclass can access .

Other modifiers

Modifier	Applied to	Description
New	Function members	Members with the same signature hide inherited members
Static	All Members	Members do not make specific instances of the class
Vritual	Function Members Only	Members can be overridden by derived classes
Abstract	Gold function member	The virtual member defines the signature of the member and does not provide the implementation code
Override	Function Members Only	A member overrides an inherited virtual or abstract member
Sealed	Classes , methods, and properties	For classes , you cannot inherit from a sealed class . For properties and Methods , a member overrides an inherited virtual member , but no member of any derived class can override the school-constant source . The modifier must be used with override
extern	static method only	Members are externally implemented in the Ning Yizhong language .

C # Programming (24)----------modifiers