Question

XAML

<Popup Name="popUpProgress" Width="225" Height="85"                   
           IsOpen="{Binding PopUpIsOpen,Mode=OneWay}"
           Placement="Center" PlacementTarget="{Binding ElementName=stkListview}" 
           VerticalAlignment="Top">
    <Border BorderThickness="1" Background="Blue"  >
        <Grid   Width="225" Height="85">
            <Grid.RowDefinitions>
                <RowDefinition Height="30" />
                <RowDefinition Height="30" />
            </Grid.RowDefinitions>
            <Label x:Name="lblProgress" Content="Please Wait ...." Margin="10,5,0,0" HorizontalAlignment="Left" Grid.Row="1" />
        </Grid>
    </Border>
</Popup>

在视图模型中：

private bool _PopUpIsOpen;

public bool PopUpIsOpen
{
    get { return _PopUpIsOpen; }
    set
    {
        _PopUpIsOpen = value;
        RaisePropertyChanged(() => this.PopUpIsOpen);
    }
}

public RelayCommand SubmitCommand { get; private set; }

private bool SubmitCommandCanExecute()
{
    return true;
}

private void SubmitCommandExecute()
{

    PopUpIsOpen = true;

    dsStandardListbyMarket = marketBL.StandardListbyMarketBL(Convert.ToInt32(SelectdMarketId), Convert.ToInt32(Users.UserId));
    GetComboboxMappingCollections(Convert.ToInt32(this.SelectdMarketId), Users.UserId);
    FItems = new ObservableCollection<MarketRecord.FItem>();
    FItems.CollectionChanged += OnUICollectionChanged;
    marketBL.FetchMarketRecords(Convert.ToInt32(this.SelectdMarketId));
    IsSubmitButtonVisible = true;

    PopUpIsOpen = false;
}

当我点击提交按钮时，控制权转到SubmitCommandExecute，但Popup窗口未显示。我对WPF有点新意，抓住了我的头。最后提出这个问题。可能是错的。

Answer 1

我认为问题在于您测试代码的方式。如果你在UI线程中睡觉，UI就不会感觉到绑定属性上从true变为false。尝试在线程中使用计时器而不是Sleep。

Answer 2

鉴于msdn上的RaisePropertyChanged语法：

protected internal void RaisePropertyChanged (
   string propertyName
)

您应该尝试RaisePropertyChanged("PopUpIsOpen");而不是RaisePropertyChanged(() => this.PopUpIsOpen);

MVVM + WPF PopUp无法打开

2 个答案: