Anyone have an explantion to me why the Style below applied to a Silverlight ListBox bound to a collection of 2000 Items leaks memory like crazy while scrolling trough the list? Memory usage goes into the hundreds of megabytes very quickly.
The leak only occurs if I leave the ItemsControl in. Otherwise memory consumption stays put. The leak also does not occur if the "Tags" property (Type: string[]) that the problematic ItemsControl is bound to returns a static readonly array from its getter.
This is the implementation of the "Tags" property getter and I have tried of calling the getters of a list items in a loop would also a leak but it doesn't. We are talking about 1-5 Tags per Collection Item = 10000 Strings at maximum. It appears as if the leak only occurs if the ItemsControl is bound to a non-static collection.
Runtime version is 4.0.60310.0 which AFAIK is higher than the one that's supposed to fix the DataTemplate MemoryLeak.
<Style x:Key="DocumentHybridListBox" TargetType="ListBox">
<Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Disabled"/>
<Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="Padding" Value="3"/>
<Setter Property="ItemsPanel">
<Setter.Value>
<ItemsPanelTemplate>
<VirtualizingStackPanel VirtualizingStackPanel.VirtualizationMode="Recycling" Orientation="Vertical" Margin="1, 3, 1, 3" />
</ItemsPanelTemplate>
</Setter.Value>
</Setter>
<Setter Property="ItemTemplate">
<Setter.Value>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Image Grid.Column="0" Style="{StaticResource DocumentList_Hybrid_Image}">
<Image.Source>
<BitmapImage Behaviors:BindableBitmapImageSource.Source="{Binding PreviewPicture}"></BitmapImage>
</Image.Source>
</Image>
<Grid Grid.Column="1" Margin="6, 0, 0, 0">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
</Grid.RowDefinitions>
<TextBlock Grid.Row="0" Text="{Binding Summary}" FontWeight="Bold" TextTrimming="WordEllipsis"></TextBlock>
<TextBlock Grid.Row="2" Text="{Binding DateSummary}" FontSize="11" TextTrimming="WordEllipsis"></TextBlock>
<!--- Problem starts here -->
<ItemsControl Grid.Row="1" ItemsSource="{Binding Tags}" Margin="0, 3, 0, 3">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal"></StackPanel>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemTemplate>
<DataTemplate>
<Button Content="{Binding}" Style="{StaticResource TagButton}"
Command="{Binding DataContext.TagDrillDownCmd, ElementName=Self}"
CommandParameter="{Binding}"
ToolTipService.ToolTip="{Binding Converter={StaticResource tagTooltipConverter}}"></Button>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</Grid>
</Grid>
</DataTemplate>
</Setter.Value>
</Setter>
</Style>
The Tags property:
private string[] _tags = null;
static readonly string[] constTags = new [] { "foo", "bar "};
public string[] Tags
{
get
{
//return constTags; // this won't leak if bound to ItemsControl
if (_tags == null)
{
// initialize
if (Document.Tags != null && Document.Tags.Length != 0)
{
// initialize
_tags = Document.Tags.Select(t => Decrypt2String(t,
ServiceLocator.Get<IKeyContainer>().DerivedContentEncryptionKey)).ToArray();
}
}
return _tags;
}
set
{
_tags = value;
OnPropertyChanged(()=>Tags);
}
}
