JavascriptDeserializer for custom collection

I have a custom collection type like below:

Namespace Collections
    Public Class KeyValuePairCollection(Of TKey, TValue)
        Inherits List(Of KeyValuePair(Of TKey, TValue))

        Public Sub New()
            MyBase.New()
        End Sub

        F开发者_如何学Goriend Sub New(ByVal innerCollection As IEnumerable(Of KeyValuePair(Of TKey, TValue)))
            Me.New()
            Me.AddRange(innerCollection)
        End Sub

        Public Overloads Sub Add(ByVal key As TKey, ByVal value As TValue)
            Dim item As New KeyValuePair(Of TKey, TValue)(key, value)
            MyBase.Add(item)
        End Sub

    End Class
End Namespace

I want to deserialize instances of this type from JSON using custom JavascriptConverter

Public Class CustomConverter(Of TKey, TValue)
        Inherits JavaScriptConverter

        Public Overrides ReadOnly Property SupportedTypes() As IEnumerable(Of Type)
            Get
                Return New ReadOnlyCollection(Of Type)(New List(Of Type) _
                 (New Type() {GetType(KeyValuePairCollection(Of TKey, TValue))}))
            End Get
        End Property

        Public Overrides Function Serialize(ByVal obj As Object, _
         ByVal serializer As JavaScriptSerializer) As IDictionary(Of String, Object)
            Throw New NotSupportedException("This class can be used only for deserialization.")
        End Function

        Public Overrides Function Deserialize(ByVal dictionary As IDictionary(Of String, Object), _
         ByVal type As Type, ByVal serializer As JavaScriptSerializer) As Object

            Return Nothing

        End Function
    End Class

Deserialization code:

Dim serializer As New JavaScriptSerializer
serializer.RegisterConverters(New CustomConverter(){New CustomConverter(Of Integer, String)})
serializer.Deserialize(Of MyClass)(serializedObject)

MyClass has a field of KeyValuePairCollection type. When I debug this code and set breakpoint to Deserialize method... this method is never called. I just get following exception:

The value "System.Collections.Generic.Dictionary2[System.String,System.Object]" is not of type "System.Collections.Generic.KeyValuePair2[System.Int32,System.String]" and cannot be used in this generic collection. Parameter name: value

NOTE

Everything is fine when I use List(Of KeyValuePair(Of Integer, String)) instead of KeyValuePairCollection(Of Integer, String) in MyClass

You are using the keyvalue pair of Integer and String when you call RegisterConverters and in CustomConverter you are looking for String, Object, so it can't be matched.

So, you may want to change your Deserialize method, but I think you will have problems doing this by extending JavaScriptConverter and you may need to do it without extending, but, I do this with C# not VB.NET so I am not certain your best approach.