Imports System.ComponentModel
Imports System.Reflection

''' <summary>
''' Contains an enumerated constant value and a friendly description of that value, if one exists.
''' </summary>
''' <typeparam name="T">
''' The enumerated type of the value.
''' </typeparam>
Public Class EnumDescriptor(Of T)

    ''' <summary>
    ''' The friendly description of the value.
    ''' </summary>
    Private _description As String
    ''' <summary>
    ''' The enumerated constant value.
    ''' </summary>
    Private _value As T

    ''' <summary>
    ''' Gets the friendly description of the value.
    ''' </summary>
    ''' <value>
    ''' A <b>String</b> containing the value's Description attribute value if one exists; otherwise, the value name.
    ''' </value>
    Public ReadOnly Property Description() As String
        Get
            Return Me._description
        End Get
    End Property

    ''' <summary>
    ''' Gets the enumerated constant value.
    ''' </summary>
    ''' <value>
    ''' An enumerated constant of the <b>EnumDescriptor's</b> generic parameter type.
    ''' </value>
    Public ReadOnly Property Value() As T
        Get
            Return Me._value
        End Get
    End Property

    ''' <summary>
    ''' Creates a new instance of the <b>EnumDescriptor</b> class.
    ''' </summary>
    ''' <param name="value">
    ''' The value to provide a description for.
    ''' </param>
    Public Sub New(ByVal value As T)
        Me._value = value

        'Get the Description attribute.
        Dim field As FieldInfo = value.GetType().GetField(value.ToString())
        Dim attributes As DescriptionAttribute() = DirectCast(field.GetCustomAttributes(GetType(DescriptionAttribute), _
                                                                                        False),  _
                                                              DescriptionAttribute())

        'Use the Description attribte if one exists, otherwise use the value itself as the description.
        Me._description = If(attributes.Length = 0, _
                             value.ToString(), _
                             attributes(0).Description)
    End Sub

    ''' <summary>
    ''' Overridden.  Creates a string representation of the object.
    ''' </summary>
    ''' <returns>
    ''' The friendly description of the value.
    ''' </returns>
    Public Overrides Function ToString() As String
        Return Me.Description
    End Function

End Class