c# - 如何在运行时更改元素样式？

Question

我有一个元素和多个样式，如何在运行时以编程方式或通过 XAML 绑定(bind)在样式之间切换。

<Rectangle x:Name="fixtureControl" Style="{DynamicResource FixtureStyle_Fast}">

<!-- In the style resources. -->
<Style x:Key="FixtureStyle_Fast" TargetType="{x:Type Shape}">
    <Setter Property="Stroke" Value="Black"/>
    <Setter Property="StrokeThickness" Value="20"/>
</Style>

<Style x:Key="FixtureStyle_Good" TargetType="{x:Type Shape}">
    <Setter Property="Effect">
        <Setter.Value>
            <DropShadowEffect Opacity=".9"
                              Direction="-90"
                              RenderingBias="Performance"
                              BlurRadius="50"
                              ShadowDepth="10" />
        </Setter.Value>
    </Setter>
</Style>

<Style x:Key="FixtureStyle_Best" TargetType="{x:Type Shape}">
    <Setter Property="Effect">
        <Setter.Value>
            <DropShadowEffect Opacity=".9"
                              Direction="-90"
                              RenderingBias="Quality"
                              BlurRadius="50"
                              ShadowDepth="10" />
        </Setter.Value>
    </Setter>
</Style>

然后我有一些处理改变样式的单选按钮

private void RadioButton_Click(object sender, RoutedEventArgs e) {
    if (e.Source == rdoQualityBest) {
        fixtureControl.Style = FindResource("FixtureStyle_Best") as Style;
    } else if (e.Source == rdoQualityGood) {
        fixtureControl.Style = FindResource("FixtureStyle_Good") as Style;
    } else {
        fixtureControl.Style = FindResource("FixtureStyle_Fast") as Style;
    }
}

然而，这会将样式应用于元素，而不是替换它，因此如果我应用 Fast 然后 Quality，我会同时获得边框和阴影。

Answer 1

这样的事情过去对我有用(纯 XAML 解决方案):

<!-- Styles 1-4 defined somewhere else on your page -->
<ComboBox Name="AvailableStyles">
    <ComboBoxItem Tag="{x:Null}" IsSelected="True">None</ComboBoxItem>
    <ComboBoxItem Tag="{StaticResource Style1}">1</ComboBoxItem>
    <ComboBoxItem Tag="{StaticResource Style2}">2</ComboBoxItem>
    <ComboBoxItem Tag="{StaticResource Style3}">3</ComboBoxItem>
    <ComboBoxItem Tag="{StaticResource Style4}">4</ComboBoxItem>
</ComboBox>

<Button Content="Button" Style="{Binding ElementName=AvailableStyles, Path=SelectedItem.Tag}"/>
<CheckBox Content="Check Box" Style="{Binding ElementName=AvailableStyles, Path=SelectedItem.Tag}"/>
<RadioButton Content="Radio Button"Style="{Binding ElementName=AvailableStyles, Path=SelectedItem.Tag}"/>

希望这对您有所帮助!