AvalonDock DocumentContent not collected garbage

Question

I created an application using the AvalonDock environment. The key part is the ability to edit domain model objects using the AvalonDock.DocumentContent editors received. I ran into a problem and found that my editors are not garbage collected after they are closed and removed from the DockingManager.Documents collection.

After some fruitless search, I created a small test application that can be recreated as follows:

• In Visual Studio (I'm using 2008), create a new WPF application called AvalonDockLeak ;
• Add a link to the AvalonDock library (my version 1.3.3571.0);
• Add a new UserControl named Document ;

• Change Document.xmal to:

   <ad:DocumentContent x:Class="AvalonDockLeak.Document" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:ad="clr-namespace:AvalonDock;assembly=AvalonDock"> <Grid> <TextBox /> </Grid> </ad:DocumentContent> 

• Change Document.xmal.cs to:

   namespace AvalonDockLeak { using AvalonDock; public partial class Document : DocumentContent { public Document() { InitializeComponent(); } ~Document() { } } } 

  The destructor that I added to diagnose the problem by adding a breakpoint when opening the {methods, and seeing if it hits. This always happens when you close the test application, but not before.

• Now change Window1.xaml to:

   <Window x:Class="AvalonDockLeak.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:ad="clr-namespace:AvalonDock;assembly=AvalonDock" Title="Memory Leak Test" Height="300" Width="300"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="Auto" /> <RowDefinition /> </Grid.RowDefinitions> <Button Name="NewButton" Click="NewButton_Click" Content="New" Height="26" Width="72" /> <ad:DockingManager x:Name="DockManager" Grid.Row="1"> <ad:DocumentPane /> </ad:DockingManager> </Grid> </Window> 

• Change Window1.xaml.cs to:

   namespace AvalonDockLeak { using System.Windows; public partial class Window1 : Window { private int counter = 0; public Window1() { InitializeComponent(); } private void NewButton_Click(object sender, RoutedEventArgs e) { string name = "Document" + (++this.counter).ToString(); var document = new Document() { Name = name, Title = name, IsFloatingAllowed = false }; document.Show(this.DockManager); document.Activate(); } } } 

This simple app also contains a leak. Which can be observed by a breakpoint when opening ~Document() {not getting after closing DocumentContent .

Now, what I want now is a known issue, and is there a way to prevent it? If objects only collect garbage after a long time, then what can I do to speed it up? Calling GC.Collect () does not help, by the way.

Answer 1

I highly recommend you and anyone using AvalonDock 1.3 to upgrade to version 2.0. The latest version is MVVM-friendly and does not suffer from this problem (documents and bindings are correctly garbage collected). Additional information: avalondock.codeplex.com

thanks

Answer 2

obviously, references to your DocumentContent are stored somewhere in the event handler. You must use a memory profiler, such as the CLR-Profiler from microsoft, to determine the cause.

You should ensure that you always unregister a registered event. otherwise, you might get a memory leak. for this you can use the - = operator.

Answer 3

DocumentContent by default hide when closed, which means that the link is stored in memory.

If you want to close the DocumentContent and subsequently delete it, you need to specify a couple of properties in the derived DocumentConcent or change the AvalonDock source.

  this.IsCloseable = true; this.HideOnClose = false; 

Now that it is closed, it will dispose of the link or hang on it, because it is simply hiding.

Answer 4

I also had a problem in this direction. Closing tabs may cause memory leak. I checked it with the profiler, and it turned out that ActiveContent would still save the link, preventing GarbageCollector from clicking.

my code to close the tab:

 dc // DocumentContent, I want to close it documentPane // DocumentPane, containing the dc documentPane.Items.Remove(dc); 

it made me close the tab, but found out that I need to call

 dc.Close(); 

before deleting content from DocumentPane if I want ActiveContent to be set to null and let GC do the job.

Note: I am using version 1.2 of AvalonDock, this can be changed in newer versions.

Answer 5

It looks like a long time outstanding error ...:

http://avalondock.codeplex.com/workitem/9113