为什么当bool变成true时，我的自定义装饰器/装饰器就不能发挥作用？

Question

所以，我对装潢师/装饰品知之甚少，但给出了一个很好的答案：这里使用它们。

我试着去实现它们，但它们似乎不像给出答案的人那样起作用。我已尽我所能使一切保持一致。

这是我的XAML：

<models:TipFocusDecorator x:Name="LoginDecorator" 
         TipText="Enter your username and password and click 'Login'"
         IsOpen="{Binding ShowLoginTip}"
         Grid.Column="1" Grid.Row="1">
    <Image Grid.Column="1" Grid.Row="1" Source="{Binding EnemyImagePath, FallbackValue={StaticResource DefaultImage}}" MaxWidth="500" MaxHeight="500">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="MouseUp">
                <i:InvokeCommandAction Command="{Binding EnemyAttack}" />
            </i:EventTrigger>
        </i:Interaction.Triggers>
    </Image>
</models:TipFocusDecorator>

public class TipFocusDecorator : Decorator
{

    public bool IsOpen
    {
        get { return (bool)GetValue(IsOpenProperty); }
        set { SetValue(IsOpenProperty, value); }
    }
    // Using a DependencyProperty as the backing store for Open.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty IsOpenProperty =
        DependencyProperty.Register("IsOpen", typeof(bool), typeof(TipFocusDecorator),
        new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, IsOpenPropertyChanged));


    public string TipText
    {
        get { return (string)GetValue(TipTextProperty); }
        set { SetValue(TipTextProperty, value); }
    }
    // Using a DependencyProperty as the backing store for TipText.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty TipTextProperty =
        DependencyProperty.Register("TipText", typeof(string), typeof(TipFocusDecorator), new UIPropertyMetadata(string.Empty));


    public bool HasBeenShown
    {
        get { return (bool)GetValue(HasBeenShownProperty); }
        set { SetValue(HasBeenShownProperty, value); }
    }

    // Using a DependencyProperty as the backing store for HasBeenShown.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty HasBeenShownProperty =
        DependencyProperty.Register("HasBeenShown", typeof(bool), typeof(TipFocusDecorator), new UIPropertyMetadata(false));

    private static void IsOpenPropertyChanged(object sender, DependencyPropertyChangedEventArgs e)
    {
        var decorator = sender as TipFocusDecorator;

        if ((bool)e.NewValue)
        {
            if (!decorator.HasBeenShown)
                decorator.HasBeenShown = true;

            decorator.Open();
        }

        if (!(bool)e.NewValue)
        {
            decorator.Close();
        }
    }

    TipFocusAdorner adorner;

    protected void Open()
    {
        adorner = new TipFocusAdorner(this.Child);
        var adornerLayer = AdornerLayer.GetAdornerLayer(this.Child);
        adornerLayer.Add(adorner);

        MessageBox.Show(TipText);  // Change for your custom tip Window
        IsOpen = false;
    }

    protected void Close()
    {
        var adornerLayer = AdornerLayer.GetAdornerLayer(this.Child);
        adornerLayer.Remove(adorner);
        adorner = null;
    }

}

下面是Adorner类：

public class TipFocusAdorner : Adorner
{
    public TipFocusAdorner(UIElement adornedElement)
        : base(adornedElement)
    {
    }

    protected override void OnRender(System.Windows.Media.DrawingContext drawingContext)
    {
        base.OnRender(drawingContext);

        var root = Window.GetWindow(this);
        var adornerLayer = AdornerLayer.GetAdornerLayer(AdornedElement);
        var presentationSource = PresentationSource.FromVisual(adornerLayer);
        Matrix transformToDevice = presentationSource.CompositionTarget.TransformToDevice;

        var sizeInPixels = transformToDevice.Transform((Vector)adornerLayer.RenderSize);
        RenderTargetBitmap rtb = new RenderTargetBitmap((int)(sizeInPixels.X), (int)(sizeInPixels.Y), 96, 96, PixelFormats.Default);

        var oldEffect = root.Effect;
        root.Effect = new BlurEffect();
        rtb.Render(root);
        root.Effect = oldEffect;

        drawingContext.DrawImage(rtb, adornerLayer.TransformToVisual(AdornedElement).TransformBounds(new Rect(adornerLayer.RenderSize)));
        drawingContext.DrawRectangle(new SolidColorBrush(Color.FromArgb(22, 0, 0, 0)), null, adornerLayer.TransformToVisual(AdornedElement).TransformBounds(new Rect(adornerLayer.RenderSize)));
        drawingContext.DrawRectangle(new VisualBrush(AdornedElement) { AlignmentX = AlignmentX.Left, TileMode = TileMode.None, Stretch = Stretch.None },
            null,
            AdornedElement.RenderTransform.TransformBounds(new Rect(AdornedElement.DesiredSize)));
    }
}

最后，这里是我的视图模型：

private ICommand testDebug;
public ICommand TestDebug
{
    get
    {
        if (testDebug == null)
        {
            testDebug = new RelayCommand(param => this.TestDebugEx(), null);
        }
        return testDebug;
    }
}
private void TestDebugEx()
{
    ShowLoginTip = true;
    OnPropertyChanged("ShowLoginTip");
}

public bool ShowLoginTip = true;

当我按下调用命令的按钮时，该命令运行良好，ShowLoginTip的值将变为true。然而，它并没有在装潢师中运行任何东西。

Answer 1

要使绑定在WPF中工作，ShowLoginToolTip应该是一个属性。

把它改成这个

private bool _showLoginToolTip;

public bool ShowLoginToolTip
{
    get
       {
         return _showLoginToolTip;
       }
    set
       {
         _showLoginToolTip = value;
         OnPropertyChanged("ShowLoginTip");
       }
}

private void TestDebugEx()
{
    ShowLoginTip = true;
}

Answer 2

我发现这个问题和我的问题很相似，这个问题解决了我的问题:我的装潢者的财产是问题所在。

当创建在更改上应该触发重绘的属性时，我更改了以下内容：

new PropertyMetadata(0.0)

对此：

new FrameworkPropertyMetadata(0.0, FrameworkPropertyMetadataOptions.AffectsRender) (在我的例子中，AffectsRender是足够的，但是YMMV)