How do I update ItemTemplate after scrambling ObservableCollection(Of ObservableCollection(Of object))

Question

I am learning vb.net, wpf and xaml with the help of sites like this one. The project I am currently working on is a 4 x 4 slide puzzle.

I cannot get the buttons in the grid to scramble to start a new game when calling a new game event. Any help will be greatly appreciated. If no answer is can be provide, a good resource to research would help as well.

Thank you for your time.

XAML:

<Window x:Class="SlidePuzzle"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Slide Puzzle" Height="391" Width="300" Name="wdw_SlidePuzzle">
<Window.Resources>


    <DataTemplate x:Key="DataTemp_PuzzleButtons">
        <Button Content="{Binding C}" 
                Height="50"
                Width="50"
                Margin="2"
                Visibility="{Binding V}"/>
    </DataTemplate>

    <DataTemplate x:Key="DataTemplate_PuzzleBoard">
        <ItemsControl ItemsSource="{Binding}" ItemTemplate="{DynamicResource DataTemp_PuzzleButtons}">
            <ItemsControl.ItemsPanel>
                <ItemsPanelTemplate>
                    <Canvas/>
                </ItemsPanelTemplate>
            </ItemsControl.ItemsPanel>
            <ItemsControl.ItemContainerStyle>
                <Style>
                    <Setter Property="Canvas.Top" Value="{Binding Path=Y}" />
                    <Setter Property="Canvas.Left" Value="{Binding Path=X}" />
                </Style>
            </ItemsControl.ItemContainerStyle>
        </ItemsControl>
    </DataTemplate>

</Window.Resources>
<DockPanel Name="dpanel_puzzle" LastChildFill="True">
    <WrapPanel DockPanel.Dock="Bottom" Margin="5" HorizontalAlignment="Center">
        <Button Name="bttnNewGame" Content="New Game" MinWidth="75" Margin="4" Click="NewGame_Click"></Button>
        <Button Name="bttnSolveGame" Content="Solve" MinWidth="75" Margin="4"></Button>
        <Button Name="bttnExitGame" Content="Exit" MinWidth="75" Margin="4" Click="ExitGame_Click"></Button>
    </WrapPanel>
    <WrapPanel DockPanel.Dock="Bottom" Margin="5" HorizontalAlignment="Center">
        <Label>Score:</Label>
        <TextBox Name="tb_Name" Width="50"></TextBox>
    </WrapPanel>
    <StackPanel Name="SlidePuzzlePnl" HorizontalAlignment="Center" VerticalAlignment="Center" Height="206" Width="206" >
        <ItemsControl x:Name="lst" ItemTemplate="{DynamicResource DataTemplate_PuzzleBoard}"/>
    </StackPanel>
</DockPanel>       

VB:

Imports System.Collections.ObjectModel

Class SlidePuzzle

Dim puzzleColl As New ObservableCollection(Of ObservableCollection(Of SlidePuzzleBttn))
Dim puzzleArr(3, 3) As Integer

Private Sub Window1_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded

    For i As Integer = 0 To 3
        puzzleColl.Add(New ObservableCollection(Of SlidePuzzleBttn))

        For j As Integer = 0 To 3
            puzzleArr(i, j) = (i * 4) + (j + 1)
            puzzleColl(i).Add(New SlidePuzzleBttn((i * 4) + (j + 1)))
            puzzleColl(i)(j).X = j * 52
            puzzleColl(i)(j).Y = i * 52
        Next
    Next

    lst.ItemsSource = puzzleColl
End Sub

Private Sub NewGame_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)

    Dim rnd As New Random
    Dim ri, rj As Integer
    Dim temp As Integer

    For i As Integer = 0 To 3
        For j As Integer = 0 To 3

            ri = rnd.Next(0, 3)
            rj = rnd.Next(0, 3)

            temp = puzzleArr(ri, rj)
            puzzleArr(ri, rj) = puzzleArr(i, j)
            puzzleArr(i, j) = temp

            puzzleColl(i)(j).X = j * 52
            puzzleColl(i)(j).Y = i * 52
            puzzleColl(i)(j).C = puzzleArr(i, j)
        Next
    Next
End Sub

End Class

Public Class SlidePuzzleBttn Inherits DependencyObject

Private _c As Integer
Private _x As Integer
Private _y As Integer
Private _v As String

Public Shared ReadOnly ContentProperty As DependencyProperty = DependencyProperty.RegisterAttached("_c", GetType(String), GetType(SlidePuzzleBttn), New UIPropertyMetadata(""))

Public Sub New()

    _c = 0
    _x = 0
    _y = 0
    _v = SetV(_c)

End Sub

Public Sub New(ByVal cVal As Integer)

    _c = cVal
    _x = 0
    _y = 0
    _v = SetV(cVal)

End Sub

Public Property C() As Integer
    Get
        Return _c
    End Get
    Set(ByVal value As Integer)
        _c = value
    End Set
End Property

Public Property X() As Integer
    Get
        Return _x
    End Get
    Set(ByVal value As Integer)
        _x = value
    End Set
End Property

Public Property Y() As Integer
    Get
        Return _y
    End Get
    Set(ByVal value As Integer)
        _y = value
    End Set
End Property

Public Property V() As String
    Get
        Return _v
    End Get
    Set(ByVal value As String)
        _v = value
    End Set
End Property

Private Function SetV(ByRef cVal As Integer) As String
    If cVal = 16 Then
        Return "Hidden"
    Else
        Return "Visible"
    End If
End Function

End Class