Question

我使用WPF，.Net 4，Prism 4.1和Unity构建了一个Prism应用程序。我正在使用DirectoryModuleCatalog在运行时查找模块。我的视图显示在TabControl（MainRegion）中。当我从区域中删除视图时，视图和视图模型将保留在内存中，并且永远不会收集垃圾 - 删除了tabitem。经过几个小时的搜索，我无法弄清楚我做错了什么。

这是我的引导程序：

public class Bootstrapper : UnityBootstrapper
{
    protected override void InitializeShell()
    {
        base.InitializeShell();
        App.Current.MainWindow = (Window)Shell;
        App.Current.MainWindow.Show();
    }

    protected override DependencyObject CreateShell()
    {
        var shell = new Shell();
        return shell;
    }

    protected override IModuleCatalog CreateModuleCatalog()
    {
        return new DirectoryModuleCatalog() { ModulePath = @".\Modules" };
    }
}

这是我的模块：

[Module(ModuleName = "ModuleA")]
public class Module : IModule
{
    private IRegionManager _regionManager;

    public Module(IRegionManager regionManager)
    {
        _regionManager = regionManager;
    }

    public void Initialize()
    {
        var view = new UserControl1();
        //_regionManager.RegisterViewWithRegion("MainRegion", typeof(UserControl1));
        _regionManager.Regions["MainRegion"].Add(view, "ModuleA");
        _regionManager.Regions["MainRegion"].Activate(view);
    }
}

以下是我的视图的视图模型，它被添加到该区域：

public class ViewModel
{
    public DelegateCommand RemoveView { get; set; }

    public ViewModel()
    {
        RemoveView = new DelegateCommand(() =>
            {
                var regionManager = ServiceLocator.Current.GetInstance<IRegionManager>();
                var view = regionManager.Regions["MainRegion"].GetView("ModuleA");
                regionManager.Regions["MainRegion"].Deactivate(view);
                regionManager.Regions["MainRegion"].Remove(view);
            });
    }
}

以下是视图背后的代码：

public partial class UserControl1 : UserControl
{
    public UserControl1()
    {
        InitializeComponent();

        this.DataContext = new ViewModel();
    }
}

我读过它可能是因为我在模块中实例化视图或者视图中的viewmodel？当我使用Red Gate Memory Profiler并通过DelegateCommand删除视图时，视图和视图模型都被标记为无法进行垃圾回收。我没有正确切割的参考在哪里？

来自Ants的保留图：https://docs.google.com/file/d/0B4XjO9pUQxBXbGFHS1luNUtyOTg/edit?usp=sharing

这是显示问题的test solution。

另外，我也在CodePlex上发布了这个问题。

Answer 1

看起来您的保留图中仍然存在对它的绑定引用。

阅读并理解以下内容：

A memory leak may occur when you use data binding in Windows Presentation Foundation

我认为这可能是你的问题，但你没有展示你的实际绑定。

Answer 2

终于找到了问题的根本原因....

在我们的Shell.xaml中，我们将其中一个按钮中的IsDefault绑定到PasswordBox的IsKeyboardFocused：

<Button Style="{DynamicResource RedSubmitButtonStyle}" IsDefault="{Binding ElementName=passwordBox1, Path=IsKeyboardFocused}" Command="{Binding LoginCommand}" Content="Login" Height="23" HorizontalAlignment="Left" Margin="145,86,0,0" Name="button1" VerticalAlignment="Top" Width="75" />

IsKeyboardFocused，是一个依赖于MSDN的依赖属性 - 因此应该是好的。

它与我们在密码框中附加的属性相关，允许我们绑定到输入的密码。即使我们隐藏了ChildWindow（来自WPF工具包扩展），焦点仍然集中在该密码框上。因此，我没有使用IsDefault，而是向PasswordBox添加了一个keydown事件，如果它是Key.Enter，我会更改焦点的UI控件并将该人员记录到程序中。

以下是我们的Shell.xaml文件的全部内容

<Grid x:Name="MainGrid" core:SharedResourceDictionary.MergedDictionaries="TabControlThemes;MenuThemes;ButtonThemes;DataGridThemes;TreeViewThemes;ComboBoxThemes;ListBoxThemes;GroupBoxThemes;ToggleSwitchThemes">

    <DockPanel>
        <ContentControl x:Name="menuContent" DockPanel.Dock="Top" prism:RegionManager.RegionName="MenuRegion" />
        <ContentControl DockPanel.Dock="Bottom" prism:RegionManager.RegionName="FooterRegion" />
        <ContentControl DockPanel.Dock="Top" prism:RegionManager.RegionName="MainContentRegion" />
    </DockPanel>

    <StackPanel Orientation="Horizontal" Panel.ZIndex="4" HorizontalAlignment="Right" VerticalAlignment="Top">
        <Button Visibility="{Binding IsFullScreenToggleVisible, Converter={StaticResource visConv}}" Command="{Binding ToggleFullScreen}" Height="50" Name="button4" Width="70" HorizontalAlignment="Right" Margin="0,10,10,0" VerticalAlignment="Top">
            <Button.Content>
                <TextBlock FontSize="12" FontWeight="Bold" TextWrapping="Wrap" TextAlignment="Center" HorizontalAlignment="Center" VerticalAlignment="Center" Text=" Toggle Full Screen" />
            </Button.Content>
        </Button>

        <Button Visibility="{Binding IsAppCloseButtonVisible, Converter={StaticResource visConv}}" Command="{Binding ShutdownApplication}" Height="50" Name="button3" Width="50" HorizontalAlignment="Right" Margin="0,10,10,0" VerticalAlignment="Top">
            <Button.Content>
                <Image Source="..\Graphics\close.png" Name="image1" />
            </Button.Content>
        </Button>
    </StackPanel>

    <xctk:ChildWindow Name="loginChildWindow" Panel.ZIndex="3" CloseButtonVisibility="Collapsed" FocusedElement="{Binding ElementName=usernameTextBox}" WindowStartupLocation="Center" WindowState="{Binding IsVisible, Mode=TwoWay, Converter={StaticResource boolConverter}}" IsModal="True" OverlayOpacity="1" Caption="Pioneer Login" Height="164" Width="261">
        <xctk:ChildWindow.OverlayBrush>
            <ImageBrush Stretch="None" Viewport="0,0,46,29" ViewportUnits="Absolute" ImageSource="../Graphics/escheresque.png" TileMode="Tile" />
        </xctk:ChildWindow.OverlayBrush>
        <xctk:BusyIndicator IsBusy="{Binding IsLoginBusy}" BusyContent="Authenticating...">
            <Grid>
                <TextBox GotFocus="usernameTextBox_GotFocus" Text="{Binding Username, UpdateSourceTrigger=PropertyChanged}" Height="23" HorizontalAlignment="Left" Margin="99,20,0,0" Name="usernameTextBox" VerticalAlignment="Top" Width="120">
                    <TextBox.InputBindings>
                        <KeyBinding Key="Enter" Command="{Binding LoginCommand}" />
                    </TextBox.InputBindings>
                </TextBox>
                <Label Content="Username" Height="28" HorizontalAlignment="Left" Margin="28,18,0,0" Name="label1" VerticalAlignment="Top" />
                <Label Content="Password" Height="28" HorizontalAlignment="Left" Margin="29,47,0,0" Name="label2" VerticalAlignment="Top" />
                <PasswordBox attach:PasswordBoxAssistant.BindPassword="True" attach:PasswordBoxAssistant.BoundPassword="{Binding Password, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" Height="23" HorizontalAlignment="Left" Margin="100,50,0,0" Name="passwordBox1" VerticalAlignment="Top" Width="120" />
                <Button Style="{DynamicResource RedSubmitButtonStyle}" IsDefault="{Binding ElementName=passwordBox1, Path=IsKeyboardFocused}" Command="{Binding LoginCommand}" Content="Login" Height="23" HorizontalAlignment="Left" Margin="145,86,0,0" Name="button1" VerticalAlignment="Top" Width="75" />
                <Button Style="{DynamicResource RedSubmitButtonStyle}" Command="{Binding LazyLoginCommand}" Visibility="{Binding IsDebugMode, Converter={StaticResource visConv}}" Content="Quick Login" Height="23" HorizontalAlignment="Left" Margin="23,87,0,0" Name="button2" VerticalAlignment="Top" Width="89" />
            </Grid>
        </xctk:BusyIndicator>
    </xctk:ChildWindow>

</Grid>

WPF＆amp; Prism 4.1垃圾收集/内存问题

2 个答案: