[英]Vb.net custom attribute to an enum
我有這個枚舉:
<Flags()>
Public Enum FilterEnum As Integer
Green= 0
Blue = 1
Red = 2
Yellow = 4
End Enum
我想給“ Green”和“ Yellow”一些屬性,所以當我得到這樣的枚舉時:
Dim enumItems = [Enum].GetValues(myEnum)
我將僅獲得具有該屬性的人的Enum值,如下所示:
Dim enumItems = [Enum].GetValues(myEnum).where(function(o) o.myAttribute)
您可以通過以下方式創建自定義屬性:
<AttributeUsage(AttributeTargets.Field)>
Public Class SomeAttribute
Inherits System.Attribute
Public Property SomeValue As String
End Class
然后創建您的枚舉並用屬性裝飾字段:
Public Enum MyEnum
<Some(SomeValue:="Good One")>
Member1 = 1
<Some(SomeValue:="Bad One")>
Member2 = 2
<Some(SomeValue:="Good One")>
Member3 = 3
End Enum
並使用此查詢,獲取所需的內容,例如“ Good One”
'Indented to be more readable step by step
Dim result As List(Of MyEnum) = _
GetType(MyEnum).GetFields() _
.Where(Function(field) _
field.GetCustomAttributes(True) _
.Cast(Of SomeAttribute) _
.Any(Function(attribute) attribute.SomeValue = "Good One")) _
.Select(Function(filtered) _
CType(filtered.GetValue(Nothing), MyEnum)) _
.ToList()
結果將是:
也許您可以使用System.ComponentModel.Description
<Flags()>
Public Enum FilterEnum As Integer
<System.ComponentModel.Description("value_1")>_
Green= 0
<System.ComponentModel.Description("value_2")>_
Blue = 1
<System.ComponentModel.Description("value_3")>_
Red = 2
<System.ComponentModel.Description("value_4")>_
Yellow = 4
End Enum
然后,檢查它們,以便從Description屬性獲取Enum
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