windows phone listbox stretch项目模板项目与ItemPanel方向水平对齐

Question

我在Windows Phone应用程序中创建一个ListBox，使项目水平对齐。我希望如果有5个项目那么他们应该平均占用空间如果有2个项目在集合中应该相应地对齐占用总宽度/ 2空间。我如何实现这一点是我写的代码：

   <ListBox x:Name="CarSelector" ItemsSource="{Binding listData}" 
                     VerticalAlignment="Center" HorizontalAlignment="Stretch" 
                     ScrollViewer.VerticalScrollBarVisibility="Disabled"
                     Background="White" 
                     ItemContainerStyle="{StaticResource SelectorContainerStyle}" 
                     Style="{StaticResource lstbxSelectorStyle}"
                     >
            <ListBox.ItemsPanel>
                <ItemsPanelTemplate>
                           <Grid>
                        <i:Interaction.Behaviors>
                            <control:GridItemPanelBehavior />
                        </i:Interaction.Behaviors>
                    </Grid>
                </ItemsPanelTemplate>
            </ListBox.ItemsPanel>
            <ListBox.ItemTemplate>
                <DataTemplate>
                            <Grid HorizontalAlignment="Stretch" 
                            >
                            <Image  Height="56"
                            Width="56"
                            VerticalAlignment="Center"
                            HorizontalAlignment="Center"
                            Source="{Binding id}" />
                            </Grid>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>

行为：

protected override void OnAttached()
        {
            base.OnAttached();

            AssociatedObject.LayoutUpdated += AssociatedObject_LayoutUpdated;
        }

        void AssociatedObject_LayoutUpdated(object sender, EventArgs e)
        {
            Grid gridItemPanel = AssociatedObject as Grid;

            var childCount = gridItemPanel.Children.Count;

            // add the required number of column definitions
            for (int row = 0; row < childCount; row++)
            {
                gridItemPanel.ColumnDefinitions.Add(new ColumnDefinition() { Width = new GridLength(1, GridUnitType.Star) });
            }

            // set the column property for each chid
            for (int i = 0; i < childCount; i++)
            {
                var child = gridItemPanel.Children[i] as FrameworkElement;
                Grid.SetColumn(child, i);
            }
        }