How to sort Enum values with dexcription in Propertygrid

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Hi,

How can I order the enum values in propertygrid by descripion?

VB

Public Class myObject
    Public Enum eFolderOrder

        <ComponentModel.Description("c")> l= 0
        <ComponentModel.Description("a")> m= 1
        <ComponentModel.Description("b")> n= 2
    End Enum


    <TypeConverter(GetType(DescriptionConverter))> <System.ComponentModel.DisplayName("MyProp")> Public Property test As eFolderOrder = eFolderOrder.Description
End Class

VB

Class DescriptionConverter
    Inherits EnumConverter
    Private _enumType As Type
    ''' <summary />Initializing instance</summary />
    ''' <param name=""type"" />type Enum</param />
    ''' this is only one function, that you must
    ''' change. All another functions for enums
    ''' you can use by Ctrl+C/Ctrl+V
    Public Sub New(type As Type)
        MyBase.New(type)
        _enumType = type
    End Sub

    Public Overrides Function CanConvertTo(context As ITypeDescriptorContext, destType As Type) As Boolean
        Return destType = GetType(String)
    End Function

    Public Overrides Function ConvertTo(context As ITypeDescriptorContext, culture As CultureInfo, value As Object, destType As Type) As Object
        Dim fi As FieldInfo = _enumType.GetField([Enum].GetName(_enumType, value))
        Dim dna As DescriptionAttribute = DirectCast(Attribute.GetCustomAttribute(fi, GetType(DescriptionAttribute)), DescriptionAttribute)

        If dna IsNot Nothing Then
            Return dna.Description
        Else
            Return value.ToString()
        End If
    End Function

    Public Overrides Function CanConvertFrom(context As ITypeDescriptorContext, srcType As Type) As Boolean
        Return srcType = GetType(String)
    End Function

    Public Overrides Function ConvertFrom(context As ITypeDescriptorContext, culture As CultureInfo, value As Object) As Object
        For Each fi As FieldInfo In _enumType.GetFields()
            Dim dna As DescriptionAttribute = DirectCast(Attribute.GetCustomAttribute(fi, GetType(DescriptionAttribute)), DescriptionAttribute)

            If (dna IsNot Nothing) AndAlso (DirectCast(value, String) = dna.Description) Then
                Return [Enum].Parse(_enumType, fi.Name)
            End If
        Next
        Return [Enum].Parse(_enumType, DirectCast(value, String))
    End Function
End Class

The shown order is:

c
a
b

but it supposed to be:

a
b
c

Thanks in advance,
Daniel

Posted 3-Nov-15 4:54am

schlumpfger

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2 solutions

Solution 2

In addition to solution 1 by Richard Deeming[^], i'd recommend to read this: Adding Descriptions to your Enumerations[^]. Even if this article uses c# code, you're able to convert it to vb.net.

Posted 3-Nov-15 7:57am

Maciej Los

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Richard Deeming · Accepted Answer · 2015-11-03T05:47:00

Override the Comparer property[^] with a custom IComparer instance that sorts as you want it to.

Something like this should work:

VB.NET

Class EnumDescriptionComparer : Implements IComparer
    Private ReadOnly _enumType As Type
    
    Public Sub New(ByVal enumType As Type)
        _enumType = enumType
    End Sub
    
    Private Function GetDescription(ByVal value As Object) As String
        Dim fi As FieldInfo = _enumType.GetField([Enum].GetName(_enumType, value))
        Dim dna As DescriptionAttribute = DirectCast(Attribute.GetCustomAttribute(fi, GetType(DescriptionAttribute)), DescriptionAttribute)
        Return If(dna Is Nothing, value.ToString(), dna.Description)
    End Function
    
    Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements IComparer.Compare
        Dim xDescription As String = GetDescription(x)
        Dim yDescription As String = GetDescription(y)
        Return StringComparer.OrdinalIgnoreCase.Compare(xDescription, yDescription)
    End Function
End Class

Class DescriptionConverter : Inherits EnumConverter
    Private ReadOnly _enumType As Type
    Private ReadOnly _comparer As IComparer
    
    Public Sub New(ByVal type As Type)
        MyBase.New(type)
        _enumType = type
        _comparer = new EnumDescriptionComparer(type)
    End Sub
    
    Protected Override ReadOnly Property Comparer As IComparer
        Get
            Return _comparer
        End Get
    End Property
    
    ...
End Class