Reputation: 412

AvalonDock DocumentContent not garbage collected

I have created an application that makes use of the AvalonDock framework. A key part is the ability to edit domain-model entities using AvalonDock.DocumentContent derived editors. I hit upon a problem and discovered the my editors are not being garbage collected after they are closed and removed from the DockingManager.Documents collection.

After some fruitless searching I created a small test application that can be recreated in the following manner:

In Visual Studio (I'm using 2008), create a new WPF application called AvalonDockLeak;
Add a reference to the AvalonDock library (my version is 1.3.3571.0);
Add a new UserControl called 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 I have added to be able to diagnose the problem adding a breakpoint on the methods opening {, and seeing if it gets hit. It always does on closing the test application but not earlier.

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 application also contains the leak. Which can be observed by the breakpoint on the ~Document() opening { not getting hit after closing a DocumentContent.

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

Upvotes: 8

Answers (5)

adospace

Reputation: 2019

I strongly suggest you and anyone using AvalonDock 1.3 to upgrade to version 2.0. Latest version is MVVM-friendly and doesn't suffer of this issue (Documents and Anchorables are correctly garbage collected). More info: avalondock.codeplex.com

Thanks

Upvotes: 1

Rashack

Reputation: 4665

This looks like a long time outstanding bug...:

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

Upvotes: 1

Robot Mess

Reputation: 959

I also had a problem in this direction. Closing tabs would cause memory leaks. I checked it with a profiler and it turned out that the ActiveContent would still keep a reference, preventing the GarbageCollector to kick in.

my code for closing the tab:

dc // DocumentContent, I want to close it
documentPane // DocumentPane, containing the dc

documentPane.Items.Remove(dc);

this did the job of closing the tab, but learned that I need to call

dc.Close();

before removing the content from the documentPane if I want ActiveContent to be set to null and let the GC do it's job.

Note: I use version 1.2 of AvalonDock, this may have changed in newer versions.

Upvotes: 1

Sheldon Cooper

Reputation: 657

obviously the references of your DocumentContent is kept by an eventhandler somewhere. you should use a memory-profiler like CLR-Profiler from microsoft to determine the cause.

you should take care that you always deregister an registered event. otherwise you can get a memory leak. for this you can use the -= operator.

Upvotes: 5

Aaron McIver

Reputation: 24713

The DocumentContent will by default hide on close, which means the reference is kept alive.

If you want the DocumentContent to close and subsequently dispose you need to specify a couple of properties within a derived DocumentConcent or modify the AvalonDock source.

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

Now when closed, it will dispose of the reference versus hanging on to it as it was merely being hidden.

Upvotes: 3

AvalonDock DocumentContent not garbage collected

Answers (5)

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