In my WP8 app, I'm using LongListSelector to display data items. Grouping works, jump list works.
I have the usual master/detail scenario here - click on item in the list, new page shows up with more information.
The problem is with navigating back to the page with LongListSelector. The list is basically messed up - items are randomly reordered, even between groups. Clicking on an item works properly - ShowItemInfo receives view model for the item the user clicked on.
Previously I was using ListBox, which too suffered from this issue. But I could disable virtualization by using default StackPanel as items panel. I don't know how to disable virtualization on LongListSelector (I don't want to, but the bug is horrible).
View model is simple. I'm using Caliburn.Micro, its conventions and BindableCollection for list of groups. I populate the list just once with AddRange method.
When the page is navigated back to, I'm not doing anything - and I even can't since I use MVVM and Caliburn.Micro. The items are loaded into list in OnInitialize callback, which is invoked only once during lifetime of view model.
The XAML for view is this:
<Grid x:Name="LayoutRoot" Background="Transparent">
<Grid.Resources>
<phone:JumpListItemBackgroundConverter x:Key="BackgroundConverter"/>
<phone:JumpListItemForegroundConverter x:Key="ForegroundConverter"/>
<Style x:Key="ListJumpListStyle" TargetType="phone:LongListSelector">
<Setter Property="ItemTemplate">
<Setter.Value>
<DataTemplate>
<Border Background="{Binding Converter={StaticResource BackgroundConverter}}"
HorizontalAlignment="Stretch">
<TextBlock Text="{Binding GroupTitle}"
Foreground="{Binding Converter={StaticResource ForegroundConverter}}" />
</Border>
</DataTemplate>
</Setter.Value>
</Setter>
</Style>
</Grid.Resources>
<phone:LongListSelector x:Name="Items" LayoutMode="List" IsGroupingEnabled="True"
JumpListStyle="{StaticResource ListJumpListStyle}">
<phone:LongListSelector.ItemTemplate>
<DataTemplate>
<Grid cal:Bind.Model="{Binding}"
cal:Message.Attach="[Event Tap] = [ShowItemInfo($dataContext)]"
Background="Transparent">
<TextBlock x:Name="ItemText" Style="{StaticResource PhoneTextTitle2Style}" />
</Grid>
</DataTemplate>
</phone:LongListSelector.ItemTemplate>
<phone:LongListSelector.GroupHeaderTemplate>
<DataTemplate>
<Border>
<TextBlock Text="{Binding GroupTitle}" />
</Border>
</DataTemplate>
</phone:LongListSelector.GroupHeaderTemplate>
</phone:LongListSelector>
</Grid>
