何时使用枚举 (Visual Basic)When to Use an Enumeration (Visual Basic)

枚举提供了一种简单的方法来处理相关的常量集。Enumerations offer an easy way to work with sets of related constants. 枚举或 Enum是一组值的符号名称。An enumeration, or Enum, is a symbolic name for a set of values. 枚举被视为数据类型,可以使用它们来创建用于变量和属性的常量集。Enumerations are treated as data types, and you can use them to create sets of constants for use with variables and properties.

何时使用枚举When to Use an Enumeration

只要过程接受有限的一组变量,就应考虑使用枚举。Whenever a procedure accepts a limited set of variables, consider using an enumeration. 枚举可用于更清晰且更易读的代码,特别是在使用有意义的名称时。Enumerations make for clearer and more readable code, particularly when meaningful names are used.

使用枚举的优点包括:The benefits of using enumerations include:

  • 减少由转置或错误错误导致的错误。Reduces errors caused by transposing or mistyping numbers.

  • 以后可以轻松地更改值。Makes it easy to change values in the future.

  • 使代码更易于阅读,这意味着错误会在其中蔓延。Makes code easier to read, which means it is less likely that errors will creep into it.

  • 确保向前兼容性。Ensures forward compatibility. 对于枚举,如果将来有人更改了与成员名称相对应的值,你的代码将不太可能失败。With enumerations, your code is less likely to fail if in the future someone changes the values corresponding to the member names.

命名枚举Naming Enumerations

为枚举成员使用命名约定。Use a naming convention for enumeration members. 当 Visual Basic 遇到枚举成员名称时,如果其他引用的类型库包含相同的名称,可能会引发异常。When Visual Basic encounters an enumeration member name, an exception may be thrown if other referenced type libraries contain the same name. 使用唯一的前缀来标识应用程序或组件中的值。Use a unique prefix that identifies the values from your application or component.

当引用枚举的成员时,必须使用枚举名称限定成员名称,否则请使用 Imports 语句。When referring to a member of an enumeration, you must qualify the member name with the enumeration name or else use the Imports statement. 有关详细信息,请参阅枚举和名称限定For more information, see Enumerations and Name Qualification.

预定义枚举Predefined Enumerations

Visual Basic 提供了许多预定义的枚举,如 FirstDayOfWeekMsgBoxResult,以便于代码。Visual Basic provides a number of predefined enumerations, such as FirstDayOfWeek and MsgBoxResult, to facilitate your code. 有关这些变量的列表,请参阅常量和枚举For a list of these see Constants and Enumerations.

另请参阅See also