IEquatable

Class FedExShipmentCollection
    Inherits CollectionBase

    Default Property Item(ByVal Index As Integer) As FedExShipment
        Get
            Return CType(List.Item(Index), FedExShipment)
        End Get
        Set(ByVal Value As FedExShipment)
            List.Item(Index) = Value
        End Set
    End Property

    Function Add(ByVal Item As FedExShipment) As Integer
        Return List.Add(Item)
    End Function
End Class

Class FedExShipmentLineItem
    Implements System.IEquatable(Of FedExShipmentLineItem)
    Private _itemDescription As System.String
    Private _countryOfOrigin As System.String
    Private _FedExShipment As FedExShipment

    Public Shadows Function Equals(ByVal other As FedExShipmentLineItem) As Boolean Implements IEquatable(Of FedExShipmentLineItem).Equals
        If other Is Nothing Then Return False
        If Me Is other Then Return True
        Return Me.ItemDescription.Equals(other.ItemDescription) AndAlso Me.CountryOfOriginCode.Equals(other.CountryOfOriginCode)
    End Function

    Public Overrides Function GetHashCode() As Integer
        Dim hashItemDescription As Integer = If(ItemDescription Is Nothing, 0, ItemDescription.GetHashCode)
        Dim hashCountyOfOrigin As Integer = If(CountryOfOriginCode Is Nothing, 0, CountryOfOriginCode.GetHashCode)
        Return hashCountyOfOrigin Xor hashItemDescription
    End Function

    Public Sub New(ByRef FedExShipment As FedExShipment)
        _FedExShipment = FedExShipment
        FedExShipment.AddLineItem(Me)
    End Sub

    Public Property ItemDescription As System.String
        Get
            Return _itemDescription
        End Get
        Set(ByVal Value As System.String)
            _itemDescription = Value
        End Set
    End Property

    Public Property CountryOfOriginCode As System.String
        Get
            Return _countryOfOrigin
        End Get
        Set(ByVal Value As System.String)
            'If Value.Length <> 2 Then Throw New ArgumentException("CountryOfOriginCode must be 2 characters.")
            _countryOfOrigin = Value
        End Set
    End Property
End Class