WinRT中的xml绑定和CollectionViewSource问题

本文关键字：CollectionViewSource 问题绑定中的 xml WinRT | 更新日期: 2023-09-27 18:14:09

在我的情况下一切都很好接受IsBusy属性，而从VM(视图模型)中的web服务获取数据时，我显式更新IsBusy = true以显示UI上的进度条，但它不工作。propertychanged总是null。进度条的可见性总是可见的它与IsBusy属性绑定。请帮助我在这里遗漏了什么。

下面是我的XAML代码:

    <local:StockVm x:Key="VM"/>
    <CollectionViewSource x:Key="CVS" Source="{Binding RequestedItems, Source={StaticResource VM}}"
                          IsSourceGrouped="True"
                          ItemsPath="StockItems"/>      
</Page.Resources>

XAML代码:

 <Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>
    <TextBlock Grid.Row="0"  Visibility="{Binding Path=IsBusy, Converter={StaticResource boolVis1}, ConverterParameter=true}">Loading...</TextBlock>
    <ProgressBar x:Name="LoadingBar" Visibility="{Binding Path=IsBusy, Converter={StaticResource boolVis1}, ConverterParameter=true}" IsIndeterminate="true" Height="4"  />
    <local:DebugListView x:Name="TheListView" Grid.Row="1" ItemsSource="{Binding Source={StaticResource CVS}}" ItemTemplate="{StaticResource ItemTemplate}" >
        <ListView.GroupStyle>
            <GroupStyle HeaderTemplate="{StaticResource StockHeaderTemplate}" HeaderContainerStyle="{StaticResource ListViewHeaderItemStyle}" />
        </ListView.GroupStyle>
    </local:DebugListView>
</Grid>

cs代码

 public TestPageDev()
        {
            this.InitializeComponent();
            _view = this.Resources["VM"] as StockVm;
            _view.LoadData();    
            this.DataContext = this; 
        }

公共类StockVm: BindableObject{

    public ObservableCollection<RequestedStock> RequestedItems
    {
        get { return _requestedItems; }
        set { SetProperty(ref _requestedItems, value); }
    }
    public StockVm()
    {
    }
    public async Task LoadData()
    {
        IsBusy = true;
        await Task.Delay(TimeSpan.FromSeconds(5));
        IsBusy = false;
    }

    #region - Public Members -
    private bool _IsBusy = false;
    public bool IsBusy
    {
        get
        {
            return _IsBusy;
        }
        set
        {
            if (_IsBusy != value)
            {
                _IsBusy = value;
                RaisePropertyEvent("IsBusy");
            }
        }
    }
    public event PropertyChangedEventHandler PropertyChanged;
    #endregion
    #region - INotifyPropertyChanged -
    private void RaisePropertyEvent(string propName)
    {
        if (PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs(propName));
    }
    #endregion
}

WinRT中的xml绑定和CollectionViewSource问题

必须将DataContext设置为视图模型实例，如下所示:

public TestPageDev()
{
    this.InitializeComponent();
    _view = this.Resources["VM"] as StockVm;
    _view.LoadData();    
    this.DataContext = _view; // here
}

(其中_view对于视图模型对象来说是一个相当奇怪的名字)。

或者像这样显式地设置绑定源:

Visibility="{Binding Path=IsBusy, Source={StaticResource VM}, ...}"