Dot-Net
如何從 VB.NET 中的列舉中獲取描述?
我有如下列舉
Public Enum FailureMessages <Description("Failed by bending")> FailedCode1 = 0 <Description("Failed by shear force")> FailedCode2 = 1 End Enum每個列舉都有自己的描述。例如,FailedCode1 有自己的描述為“彎曲失敗”。
下面是我的主要 Sub() ,我想將一個變數(類型字元串)分配給相應的列舉。
Sub Main() Dim a As Integer = FailureMessages.FailedCode1 Dim b As String 'I would b = Conresponding description of variable a above 'that means: I would b will be "Failed by bending". How could I do that in .NET ? End Sub誰能幫助我,我怎麼能在 VB.NET 中做到這一點
您需要使用
Reflection來檢索Description. 由於這些是使用者添加的,因此可能會失去一個或多個,我希望它返回Name如果Attribute失去。Imports System.Reflection Imports System.ComponentModel Public Shared Function GetEnumDescription(e As [Enum]) As String Dim t As Type = e.GetType() Dim attr = CType(t. GetField([Enum].GetName(t, e)). GetCustomAttribute(GetType(DescriptionAttribute)), DescriptionAttribute) If attr IsNot Nothing Then Return attr.Description Else Return e.ToString End If End Function用法:
Dim var As FailureMessages = FailureMessages.FailedCode1 Dim txt As String = GetDescription(var)您可以創建一個版本來獲取所有說明
Enum:Friend Shared Function GetEnumDescriptions(Of EType)() As String() Dim n As Integer = 0 ' get values to poll Dim enumValues As Array = [Enum].GetValues(GetType(EType)) ' storage for the result Dim Descr(enumValues.Length - 1) As String ' get description or text for each value For Each value As [Enum] In enumValues Descr(n) = GetEnumDescription(value) n += 1 Next Return Descr End Function用法:
Dim descr = Utils.GetDescriptions(Of FailureMessages)() ComboBox1.Items.AddRange(descr)
Of T使它更容易使用。傳遞類型將是:Shared Function GetEnumDescriptions(e As Type) As String() ' usage: Dim items = Utils.GetEnumDescriptions(GetType(FailureMessages))請注意,使用名稱填充組合意味著您需要解析結果以獲取值。相反,我發現將所有名稱和值放入 a
List(Of NameValuePairs)以將它們保持在一起會更好/更容易。您可以將控制項綁定到列表並用於
DisplayMember向使用者顯示名稱,而程式碼用於ValueMember取回實際鍵入的值。