Question

我有一个带有圆角的边框元素，包含一个3x3网格。网格的角落伸出边界。我该如何解决这个问题？我尝试使用ClipToBounds但没有得到任何结果。谢谢你的帮助

Answer 1

以下是thread

提到的Jobi的重点

装饰器（即Border）或布局面板（即Stackpanel）都没有开箱即用的这种行为。
ClipToBounds用于布局。 ClipToBounds不会阻止元素在其边界之外绘制;它只是防止儿童的布局“溢出”。此外，大多数元素都不需要ClipToBounds = True，因为它们的实现不允许其内容的布局溢出。最值得注意的例外是Canvas。
最后，Border将圆角视为其布局范围内的绘图。

这是一个继承自Border并实现正确功能的类的实现：

     /// <Remarks>
    ///     As a side effect ClippingBorder will surpress any databinding or animation of 
    ///         its childs UIElement.Clip property until the child is removed from ClippingBorder
    /// </Remarks>
    public class ClippingBorder : Border {
        protected override void OnRender(DrawingContext dc) {
            OnApplyChildClip();            
            base.OnRender(dc);
        }

        public override UIElement Child 
        {
            get
            {
                return base.Child;
            }
            set
            {
                if (this.Child != value)
                {
                    if(this.Child != null)
                    {
                        // Restore original clipping
                        this.Child.SetValue(UIElement.ClipProperty, _oldClip);
                    }

                    if(value != null)
                    {
                        _oldClip = value.ReadLocalValue(UIElement.ClipProperty);
                    }
                    else 
                    {
                        // If we dont set it to null we could leak a Geometry object
                        _oldClip = null;
                    }

                    base.Child = value;
                }
            }
        }

        protected virtual void OnApplyChildClip()
        {
            UIElement child = this.Child;
            if(child != null)
            {
                _clipRect.RadiusX = _clipRect.RadiusY = Math.Max(0.0, this.CornerRadius.TopLeft - (this.BorderThickness.Left * 0.5));
                _clipRect.Rect = new Rect(Child.RenderSize);
                child.Clip = _clipRect;
            }
        }

        private RectangleGeometry _clipRect = new RectangleGeometry();
        private object _oldClip;
    }

Answer 2

Pure XAML：

<Border CornerRadius="30" Background="Green">
    <Border.OpacityMask>
        <VisualBrush>
            <VisualBrush.Visual>
                <Border 
                    Background="Black"
                    SnapsToDevicePixels="True"
                    CornerRadius="{Binding CornerRadius, RelativeSource={RelativeSource AncestorType=Border}}"
                    Width="{Binding ActualWidth, RelativeSource={RelativeSource AncestorType=Border}}"
                    Height="{Binding ActualHeight, RelativeSource={RelativeSource AncestorType=Border}}"
                    />
            </VisualBrush.Visual>
        </VisualBrush>
    </Border.OpacityMask>
    <TextBlock Text="asdas das d asd a sd a sda" />
</Border>

<强>更新找到了实现相同结果的更好方法。您现在也可以将 Border 替换为任何其他元素。

<Grid>
    <Grid.OpacityMask>
        <VisualBrush Visual="{Binding ElementName=Border1}" />
    </Grid.OpacityMask>
    <Border x:Name="Border1" CornerRadius="30" Background="Green" />
    <TextBlock Text="asdas das d asd a sd a sda" />
</Grid>

Answer 3

所以我刚刚遇到了这个解决方案，然后进入了Jobi提供的msdn论坛链接，花了20分钟编写我自己的ClippingBorder控件。

然后我意识到CornerRadius属性类型不是double，而是System.Windows.CornerRaduis，它接受4个双打，每个角落一个。

所以我现在要列出另一种替代解决方案，这很可能会满足大多数将来偶然发现这篇文章的人的要求......

假设您有XAML，如下所示：

<Border CornerRadius="10">
    <Grid>
        ... your UI ...
    </Grid>
</Border>

问题是Grid元素的背景渗透并显示过去的圆角。确保您的<Grid>具有透明背景，而不是将同一笔刷分配给<Border>元素的“背景”属性。没有更多的流血过去，也不需要一大堆CustomControl代码。

理论上，客户区域仍有可能超越角落边缘，但您可以控制该内容，因此您作为开发人员应该能够拥有足够的填充，或者确保控件的形状在边缘旁边是合适的（在我的情况下，我的按钮是圆的，所以非常适合在角落没有任何问题）。

Answer 4

正如Micah所说，ClipToBounds不适用于Border.ConerRadius。

有UIElement.Clip属性，Border继承。

如果你知道边框的确切大小，那么这就是解决方案：

<Border Background="Blue" CornerRadius="3" Height="100" Width="100">
      <Border.Clip>
        <RectangleGeometry RadiusX="3" RadiusY="3" Rect="0,0,100,100"/>
      </Border.Clip>
      <Grid Background="Green"/>
</Border>

如果尺寸未知或动态，则可以使用Converter的{{1}}。请参阅解决方案here。

Answer 5

使用@Andrew Mikhailov的解决方案，您可以定义一个简单的类，这样就可以手动为每个受影响的元素定义VisualBrush：

public class ClippedBorder : Border
{
    public ClippedBorder() : base()
    {
        var e = new Border()
        {
            Background = Brushes.Black,
            SnapsToDevicePixels = true,
        };
        e.SetBinding(Border.CornerRadiusProperty, new Binding()
        {
            Mode = BindingMode.OneWay,
            Path = new PropertyPath("CornerRadius"),
            Source = this
        });
        e.SetBinding(Border.HeightProperty, new Binding()
        {
            Mode = BindingMode.OneWay,
            Path = new PropertyPath("ActualHeight"),
            Source = this
        });
        e.SetBinding(Border.WidthProperty, new Binding()
        {
            Mode = BindingMode.OneWay,
            Path = new PropertyPath("ActualWidth"),
            Source = this
        });

        OpacityMask = new VisualBrush(e);
    }
}

要测试这个，只需编译以下两个样本：

<!-- You should see a blue rectangle with rounded corners/no red! -->
<Controls:ClippedBorder
    Background="Red"
    CornerRadius="10"
    Height="425"
    HorizontalAlignment="Center"
    VerticalAlignment="Center"
    Width="425">
    <Border Background="Blue">
    </Border>
</Controls:ClippedBorder>

<!-- You should see a blue rectangle with NO rounded corners/still no red! -->
<Border
    Background="Red"
    CornerRadius="10"
    Height="425"
    HorizontalAlignment="Center"
    VerticalAlignment="Center"
    Width="425">
    <Border Background="Blue">
    </Border>
</Border>

Answer 6

使网格更小或边框更大。这样border元素就完全包含了网格。

或者看看你是否可以使网格的背景透明，以便“伸出”不明显。

更新：哎呀，没注意到这是一个WPF问题。我不熟悉。这是一般的HTML / CSS建议。也许它有帮助...

Answer 7

我不喜欢使用自定义控件。而是创建了一个行为。

using System.Linq;
using System.Windows;
using System.Windows.Interactivity;

/// <summary>
/// Base class for behaviors that could be used in style.
/// </summary>
/// <typeparam name="TComponent">Component type.</typeparam>
/// <typeparam name="TBehavior">Behavior type.</typeparam>
public class AttachableForStyleBehavior<TComponent, TBehavior> : Behavior<TComponent>
        where TComponent : System.Windows.DependencyObject
        where TBehavior : AttachableForStyleBehavior<TComponent, TBehavior>, new()
{
#pragma warning disable SA1401 // Field must be private.

    /// <summary>
    /// IsEnabledForStyle attached property.
    /// </summary>
    public static DependencyProperty IsEnabledForStyleProperty =
        DependencyProperty.RegisterAttached("IsEnabledForStyle", typeof(bool),
        typeof(AttachableForStyleBehavior<TComponent, TBehavior>), new FrameworkPropertyMetadata(false, OnIsEnabledForStyleChanged));

#pragma warning restore SA1401

    /// <summary>
    /// Sets IsEnabledForStyle value for element.
    /// </summary>
    public static void SetIsEnabledForStyle(UIElement element, bool value)
    {
        element.SetValue(IsEnabledForStyleProperty, value);
    }

    /// <summary>
    /// Gets IsEnabledForStyle value for element.
    /// </summary>
    public static bool GetIsEnabledForStyle(UIElement element)
    {
        return (bool)element.GetValue(IsEnabledForStyleProperty);
    }

    private static void OnIsEnabledForStyleChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        UIElement uie = d as UIElement;

        if (uie != null)
        {
            var behColl = Interaction.GetBehaviors(uie);
            var existingBehavior = behColl.FirstOrDefault(b => b.GetType() ==
                  typeof(TBehavior)) as TBehavior;

            if ((bool)e.NewValue == false && existingBehavior != null)
            {
                behColl.Remove(existingBehavior);
            }
            else if ((bool)e.NewValue == true && existingBehavior == null)
            {
                behColl.Add(new TBehavior());
            }
        }
    }
}

using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Media;

/// <summary>
/// Behavior that creates opacity mask brush.
/// </summary>
internal class OpacityMaskBehavior : AttachableForStyleBehavior<Border, OpacityMaskBehavior>
{
    protected override void OnAttached()
    {
        base.OnAttached();

        var border = new Border()
        {
            Background = Brushes.Black,
            SnapsToDevicePixels = true,
        };

        border.SetBinding(Border.CornerRadiusProperty, new Binding()
        {
            Mode = BindingMode.OneWay,
            Path = new PropertyPath("CornerRadius"),
            Source = AssociatedObject
        });

        border.SetBinding(FrameworkElement.HeightProperty, new Binding()
        {
            Mode = BindingMode.OneWay,
            Path = new PropertyPath("ActualHeight"),
            Source = AssociatedObject
        });

        border.SetBinding(FrameworkElement.WidthProperty, new Binding()
        {
            Mode = BindingMode.OneWay,
            Path = new PropertyPath("ActualWidth"),
            Source = AssociatedObject
        });

        AssociatedObject.OpacityMask = new VisualBrush(border);
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();

        AssociatedObject.OpacityMask = null;
    }
}

<Style x:Key="BorderWithRoundCornersStyle" TargetType="{x:Type Border}">
    <Setter Property="CornerRadius" Value="50" />
    <Setter Property="behaviors:OpacityMaskBehavior.IsEnabledForStyle" Value="True" />
</Style>

如何制作圆角边框的内容也是圆角的？

7 个答案: