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📜  VB.Net-修饰符

📅  最后修改于: 2020-11-19 08:46:45             🧑  作者: Mango

修饰符是与任何编程元素一起添加的关键字，以特别强调编程元素的行为方式或在程序中的访问方式。

例如，访问修饰符：“公共”，“私有”，“受保护”，“朋友”，“受保护的朋友”等，指示编程元素的访问级别，例如变量，常量，枚举或类。

VB.Net中可用的修饰符列表

下表提供了VB.Net修饰符的完整列表-

Sr.No Modifier Description
1 Ansi Specifies that Visual Basic should marshal all strings to American National Standards Institute (ANSI) values regardless of the name of the external procedure being declared.
2 Assembly Specifies that an attribute at the beginning of a source file applies to the entire assembly.
3 Async Indicates that the method or lambda expression that it modifies is asynchronous. Such methods are referred to as async methods. The caller of an async method can resume its work without waiting for the async method to finish.
4 Auto The charsetmodifier part in the Declare statement supplies the character set information for marshaling strings during a call to the external procedure. It also affects how Visual Basic searches the external file for the external procedure name. The Auto modifier specifies that Visual Basic should marshal strings according to .NET Framework rules.
5 ByRef Specifies that an argument is passed by reference, i.e., the called procedure can change the value of a variable underlying the argument in the calling code. It is used under the contexts of −
  • Declare Statement
  • Function Statement
  • Sub Statement
6 ByVal Specifies that an argument is passed in such a way that the called procedure or property cannot change the value of a variable underlying the argument in the calling code. It is used under the contexts of −
  • Declare Statement
  • Function Statement
  • Operator Statement
  • Property Statement
  • Sub Statement
7 Default Identifies a property as the default property of its class, structure, or interface.
8 Friend

Specifies that one or more declared programming elements are accessible from within the assembly that contains their declaration, not only by the component that declares them.

Friend access is often the preferred level for an application’s programming elements, and Friend is the default access level of an interface, a module, a class, or a structure.
9 In It is used in generic interfaces and delegates.
10 Iterator Specifies that a function or Get accessor is an iterator. An iterator performs a custom iteration over a collection.
11 Key The Key keyword enables you to specify behavior for properties of anonymous types.
12 Module Specifies that an attribute at the beginning of a source file applies to the current assembly module. It is not same as the Module statement.
13 MustInherit Specifies that a class can be used only as a base class and that you cannot create an object directly from it.
14 MustOverride Specifies that a property or procedure is not implemented in this class and must be overridden in a derived class before it can be used.
15 Narrowing Indicates that a conversion operator (CType) converts a class or structure to a type that might not be able to hold some of the possible values of the original class or structure.
16 NotInheritable Specifies that a class cannot be used as a base class.
17 NotOverridable Specifies that a property or procedure cannot be overridden in a derived class.
18 Optional Specifies that a procedure argument can be omitted when the procedure is called.
19 Out For generic type parameters, the Out keyword specifies that the type is covariant.
20 Overloads Specifies that a property or procedure redeclares one or more existing properties or procedures with the same name.
21 Overridable Specifies that a property or procedure can be overridden by an identically named property or procedure in a derived class.
22 Overrides Specifies that a property or procedure overrides an identically named property or procedure inherited from a base class.
23 ParamArray ParamArray allows you to pass an arbitrary number of arguments to the procedure. A ParamArray parameter is always declared using ByVal.
24 Partial Indicates that a class or structure declaration is a partial definition of the class or structure.
25 Private Specifies that one or more declared programming elements are accessible only from within their declaration context, including from within any contained types.
26 Protected Specifies that one or more declared programming elements are accessible only from within their own class or from a derived class.
27 Public Specifies that one or more declared programming elements have no access restrictions.
28 ReadOnly Specifies that a variable or property can be read but not written.
29 Shadows Specifies that a declared programming element redeclares and hides an identically named element, or set of overloaded elements, in a base class.
30 Shared Specifies that one or more declared programming elements are associated with a class or structure at large, and not with a specific instance of the class or structure.
31 Static Specifies that one or more declared local variables are to continue to exist and retain their latest values after termination of the procedure in which they are declared.
32 Unicode Specifies that Visual Basic should marshal all strings to Unicode values regardless of the name of the external procedure being declared.
33 Widening Indicates that a conversion operator (CType) converts a class or structure to a type that can hold all possible values of the original class or structure.
34 WithEvents Specifies that one or more declared member variables refer to an instance of a class that can raise events.
35 WriteOnly Specifies that a property can be written but not read.