Question

首先，我有两个页面叫做MainPage和BindPage。 MainPage可以导航到BindPage。 BindPage有两个绑定：

一个是xaml中的DataContext绑定：

<Page x:Class="MvvmlightTest.View.BindingPage"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:local="using:MvvmlightTest.View"
  xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
  mc:Ignorable="d"
  xmlns:cvt="using:MvvmlightTest.Converter"
  DataContext="{Binding BindingVM, Source={StaticResource Locator}, Mode=OneWay}"
  Unloaded="Page_Unloaded">

另一个绑定在页面内容中：

        <Grid Background="#7F919191"
          Visibility="{x:Bind VM.IsInBuyProcess, Mode=OneWay, Converter={StaticResource BooleanToVisibilityConverter}}">
            <ProgressRing Width="100"
                      Height="100"
                      HorizontalAlignment="Center"
                      VerticalAlignment="Center"
                      IsActive="True" />
        </Grid>

VM的定义是：

    public BindingViewModel VM
    {
        get
        {
            return DataContext as BindingViewModel;
        }
    }

BindingViewModel只有一个属性：

    private bool isInBuyProcess;

    public bool IsInBuyProcess
    {
        get
        {
            return true;
        }
        set
        {
            isInBuyProcess = value;
        }
    }

我还需要显示BindPage.g.cs，它包含两个重要的类：BindingPage_obj1_Bindings＆amp; BindingPage_obj1_BindingsTracking

BindingPage_obj1_BindingsTracking是BindingPage_obj1_Bindings的成员

        public BindingPage_obj1_BindingsTracking bindingsTracking;

        public BindingPage_obj1_Bindings()
        {
            this.bindingsTracking = new BindingPage_obj1_BindingsTracking(this);
            Tk = new WeakReference<BindingPage_obj1_BindingsTracking>(this.bindingsTracking);
        }

BindingPage_obj1_Bindings在这里初始化：

    public global::Windows.UI.Xaml.Markup.IComponentConnector GetBindingConnector(int connectionId, object target)
    {
        global::Windows.UI.Xaml.Markup.IComponentConnector returnValue = null;
        switch(connectionId)
        {
        case 1:
            {
                global::Windows.UI.Xaml.Controls.Page element1 = (global::Windows.UI.Xaml.Controls.Page)target;
                BindingPage_obj1_Bindings bindings = new BindingPage_obj1_Bindings();
                returnValue = bindings;
                bindings.SetDataRoot(this);
                bindings.SetConverterLookupRoot(this);
                this.Bindings = bindings;
                element1.Loading += bindings.Loading;
            }
            break;
        }
        return returnValue;
    }

BindingPage_obj1_BindingsTracking无法在BindingPage_obj1_Bindings之外发布

        private void StopTracking()
        {
            this.bindingsTracking.ReleaseAllListeners();
            this.initialized = false;
        }

            private void ReleaseAllListeners()
            {
                UpdateChildListeners_VM(null);
            }

            private void UpdateChildListeners_VM(global::MvvmlightTest.ViewModel.BindingViewModel obj)
            {
                if (obj != cache_VM)
                {
                    if (cache_VM != null)
                    {
                        ((global::System.ComponentModel.INotifyPropertyChanged)cache_VM).PropertyChanged -= PropertyChanged_VM;
                        cache_VM = null;
                    }
                    if (obj != null)
                    {
                        cache_VM = obj;
                        ((global::System.ComponentModel.INotifyPropertyChanged)obj).PropertyChanged += PropertyChanged_VM;
                    }
                }
            }

从 MainPage 导航到 BindPage ，然后返回GC集合后，可以释放BindPage和BindingPage_obj1_Binding但BindingPage_obj1_BindingsTracking NOT

如果我将DataContext绑定移动到代码隐藏并将其写入Page_Loaded事件，则将释放BindingPage_obj1_BindingsTracking。

那么，结果是否意味着x：Bind不能与Binding一起使用？

btw，我的测试项目here

======================更新======================

几天后，我找到了结果。解决方案非常简单，只需在 Page_Unloaded 方法中调用 Bindings.StopTracking（），因此应该释放所有单向绑定和双向绑定。

解决方案不是使用MVVM实现更多功能的好方法，因为Bindings属性是私有的，我们需要在代码隐藏中调用该函数。我不太清楚为什么Microsoft会将绑定生成私有。

x：绑定将在xaml

0 个答案: