visual basic 2010 broncode voorbeelden

Namespace HashtableUsesEqualsExample
    Class SomeKey
        Public Value As Integer
        Public Overrides Function Equals(ByVal obj As Object) As Boolean
            If obj IsNot Nothing AndAlso TypeOf obj Is SomeKey Then
                Equals = (Me.Value = DirectCast(obj, SomeKey).Value)
            End If
        End Function
        Public Overrides Function GetHashCode() As Integer
            GetHashCode = Value
        End Function
    End Class
    Class SomeValue
        Public Value As Integer
        Public Overrides Function Equals(ByVal obj As Object) As Boolean
            If obj IsNot Nothing AndAlso TypeOf obj Is SomeValue Then
                Equals = (Me.Value = DirectCast(obj, SomeValue).Value)
            End If
        End Function
        Public Overrides Function GetHashCode() As Integer
            GetHashCode = Value
        End Function
        Public Name As String
        Public Overrides Function ToString() As String
            ToString = Name
        End Function
    End Class
    Class Client
        Public Shared Sub Main()
            Dim key1 As New SomeKey With {.Value = 1}
            Dim key2 As New SomeKey With {.Value = 2}
            Dim key3 As New SomeKey With {.Value = 1}
            '
            Dim value1 As New SomeValue With {.Value = 1, .Name = "value1"}
            Dim value2 As New SomeValue With {.Value = 1, .Name = "value2"}
            Dim value3 As New SomeValue With {.Value = 3, .Name = "value3"}
            '
            Dim hashtable1 As New Hashtable
            '
            hashtable1.Add(key1, value1)
            '
            Console.WriteLine(hashtable1.Contains(key1))        ' True
            Console.WriteLine(hashtable1.Contains(key2))        ' False
            Console.WriteLine(hashtable1.Contains(key3))        ' True
            Console.WriteLine()
            '
            Console.WriteLine(hashtable1.ContainsKey(key1))     ' True
            Console.WriteLine(hashtable1.ContainsKey(key2))     ' False
            Console.WriteLine(hashtable1.ContainsKey(key3))     ' True
            Console.WriteLine()
            '
            Console.WriteLine(hashtable1.ContainsValue(value1)) ' True
            Console.WriteLine(hashtable1.ContainsValue(value2)) ' True
            Console.WriteLine(hashtable1.ContainsValue(value3)) ' False
            Console.WriteLine()
            '
            Console.WriteLine(hashtable1.Item(key1).ToString()) ' value1
            Console.WriteLine(hashtable1.Item(key2) Is Nothing) ' True
            Console.WriteLine(hashtable1.Item(key3).ToString()) ' value1    (1)
            Console.WriteLine()
            '
            Console.WriteLine(hashtable1.Count)                 ' 1
            '
            hashtable1.Remove(key3)                                       ' (2)
            '
            Console.WriteLine(hashtable1.ContainsKey(key1))     ' False
            Console.WriteLine(hashtable1.Count)                 ' 0
            ''
            Console.ReadLine()
        End Sub
    End Class
End Namespace

True
False
True

True
False
True

True
True
False

value1
True
value1

1
False
0