memory cleanup issue inside listbox / detaching the trigger issue - windows-phone-7

Question

<listbox>
<ListBox.ItemTemplate>
<DataTemplate>
<Grid Height="120" Width="480" VerticalAlignment="Top">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="110"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Border
Height="105"
Width="110"
BorderBrush="White"
Grid.Column="0"
BorderThickness="2">
<Image
delay:LowProfileImageLoader.UriSource="{Binding Path=Avatar}"
Source="/Image/default-thumb-groups.png">
</Image>
</Border>
<Grid Grid.Column="1">
<Grid.RowDefinitions>
<RowDefinition Height="4"/>
<RowDefinition Height="35"/>
<RowDefinition Height="50"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="10" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<TextBlock
Text="{Binding Path=Name,Mode=TwoWay}"
Grid.Column="1"
Grid.Row="1"
FontFamily="Segoe WP Light"
FontSize="26"
Foreground="{StaticResource PhoneForegroundBrush}"
TextWrapping="Wrap">
</TextBlock>
<TextBlock
Text="{Binding Path=Members,Mode=TwoWay}"
Grid.Column="2"
Grid.Row="2"
FontFamily="Segoe WP Light"
HorizontalAlignment="Left"
FontSize="20" Opacity="0.91"
Foreground="{StaticResource PhoneForegroundBrush}"
TextWrapping="Wrap">
</TextBlock>
<toolkit:ContextMenuService.ContextMenu>
<toolkit:ContextMenu
Name="DeleteGroup"
IsZoomEnabled="False"
Tag="{Binding Nid,Mode=TwoWay}"
Visibility="{Binding ElementName=GroupList, Path=DataContext.DeleteStatus,Mode=TwoWay, Converter=
{StaticResource booleanToVisibility}}" Opened="DeleteGroup_Opened" Closed="DeleteGroup_Opened">
<toolkit:MenuItem Header="delete group">
<Interactivity:Interaction.Triggers>
<Interactivity:EventTrigger EventName="Click">
<Command:EventToCommand Command="{Binding ElementName=GroupList,
Path=DataContext.DeleteCommand,Mode=TwoWay}" CommandParameter="{Binding
ElementName=DeleteGroup}" PassEventArgsToCommand="True"/>
</Interactivity:EventTrigger>
</Interactivity:Interaction.Triggers>
</toolkit:MenuItem>
</toolkit:ContextMenu>
</toolkit:ContextMenuService.ContextMenu>
</Grid>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
While trying for cleanup ; The Trigger of Context menu is not Detaching ; Because of this that page is not Dying even after navigating back from the page. This causing Saviour memory issue in our page. Please help me to resolve this Issue

Answer 1

Never worked with the Toolkit ContextMenu, but noticed that you are not the only one having similar problem. For example this article proves that "the ContextMenu control attaches itself to the RootVisual via mouse event handlers and therefore never gets GC'ed; even worse, the visual tree it is placed in is kept alive as well". Even if that article talks about the desktop, the symptoms are probably the same on WP7.
I would try to create/destroy menu programatically. This article demonstrates the techniques that can be used.
Another possibility would be to customize the listbox:
Override PrepareContainerForItemOverride: Call base.PrepareContainerForItemOverride() to get the standard ListBoxItem and add ContextMenu to it manually.
Override ClearContainerForItemOverride to clear the menu reference.
(Never tried that, but it should work.)
A side remark
Your Xaml seems to be overcomplicated to me. If nothing else, then using nested grids within ListBoxItem (which in turn is embedded into ListBox panel (VirtualizingStackPanel), which is in at least one more panel on the page level) must have terrible perf impact.
Even if I forget that the internal 4x2 grid uses 2 cells only (perhaps you simplified presented Xaml), what's the purpose of the outer grid? The same effect can be achieved by using a single grid and column span over the first column.