在鼠标悬停时使按钮透明

Question

我正在使用 Microsoft Visual Studio Express 2012 构建一个 Metro 风格的应用程序。我对这个应用程序非常陌生，我需要帮助。我在 XAML 中定义了一个按钮，按钮背景是从图像中设置的。鼠标悬停在按钮上时，其背景变为空白。我想改变它，使图像在鼠标悬停时大约透明 50%。那可能吗？有什么帮助吗？谢谢。

我已将按钮声明如下：

<Button Height="100" Width="100" Margin="0,0,0,0">
  <Button.Background>
    <ImageBrush ImageSource="../Images/home.png"></ImageBrush>
  </Button.Background>
</Button>

Answer 1

Windows 应用商店应用不存在 Interactivity dll。您应该改用视觉状态。使用 Blend 很容易实现。

如果您在 Blend 中打开应用并编辑按钮模板的副本，您最终会在 xaml 中获得完整的默认按钮样式。您只需编辑 PointerOver 视觉状态即可实现您想要的效果。

您的按钮将如下所示：

<Button Height="100" Width="100" Margin="0,0,0,0" Style="{StaticResource ButtonStyle1}">
    <Button.Background>
        <ImageBrush ImageSource="/Assets/Images/home.png"></ImageBrush>
    </Button.Background>
</Button>

您必须在应用的资源中定义样式，以便您可以在任何地方使用它。

在下面的代码中，查看 PointerOver 视觉状态。它定义了按钮在进入该状态时应如何更改。在这里，我们说边框的不透明度（即显示背景图像的内容）应该是 0.5：

<DoubleAnimation Duration="0" To="0.5" Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="Border" d:IsOptimized="True"/>

这是完整的样式：

<Style x:Key="ButtonStyle1" TargetType="Button">
    <Setter Property="Background" Value="{StaticResource ButtonBackgroundThemeBrush}"/>
    <Setter Property="Foreground" Value="{StaticResource ButtonForegroundThemeBrush}"/>
    <Setter Property="BorderBrush" Value="{StaticResource ButtonBorderThemeBrush}"/>
    <Setter Property="BorderThickness" Value="{StaticResource ButtonBorderThemeThickness}"/>
    <Setter Property="Padding" Value="12,4,12,4"/>
    <Setter Property="HorizontalAlignment" Value="Left"/>
    <Setter Property="VerticalAlignment" Value="Center"/>
    <Setter Property="FontFamily" Value="{StaticResource ContentControlThemeFontFamily}"/>
    <Setter Property="FontWeight" Value="SemiBold"/>
    <Setter Property="FontSize" Value="{StaticResource ControlContentThemeFontSize}"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="Button">
                <Grid>
                    <VisualStateManager.VisualStateGroups>
                        <VisualStateGroup x:Name="CommonStates">
                            <VisualState x:Name="Normal"/>
                            <VisualState x:Name="PointerOver">
                                <Storyboard>
                                    <DoubleAnimation Duration="0" To="0.5" Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="Border" d:IsOptimized="True"/>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="Pressed">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="Border">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource ButtonPressedBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentPresenter">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource ButtonPressedForegroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="Disabled">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="Border">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource ButtonDisabledBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="Border">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource ButtonDisabledBorderThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentPresenter">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource ButtonDisabledForegroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                        </VisualStateGroup>
                        <VisualStateGroup x:Name="FocusStates">
                            <VisualState x:Name="Focused">
                                <Storyboard>
                                    <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="FocusVisualWhite"/>
                                    <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="FocusVisualBlack"/>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="Unfocused"/>
                            <VisualState x:Name="PointerFocused"/>
                        </VisualStateGroup>
                    </VisualStateManager.VisualStateGroups>
                    <Border x:Name="Border" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Margin="3">
                        <ContentPresenter x:Name="ContentPresenter" ContentTemplate="{TemplateBinding ContentTemplate}" ContentTransitions="{TemplateBinding ContentTransitions}" Content="{TemplateBinding Content}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                    </Border>
                    <Rectangle x:Name="FocusVisualWhite" IsHitTestVisible="False" Opacity="0" StrokeDashOffset="1.5" StrokeEndLineCap="Square" Stroke="{StaticResource FocusVisualWhiteStrokeThemeBrush}" StrokeDashArray="1,1"/>
                    <Rectangle x:Name="FocusVisualBlack" IsHitTestVisible="False" Opacity="0" StrokeDashOffset="0.5" StrokeEndLineCap="Square" Stroke="{StaticResource FocusVisualBlackStrokeThemeBrush}" StrokeDashArray="1,1"/>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>