在 WPF 中动态更改样式 [英] Change a style dynamically in WPF

问题描述

有没有办法在 WPF 中动态更改(和应用)样式?

Is there a way to change(and apply) a style dynamically in WPF?

假设我在 XAML 中声明了样式:

Say I have the style declared in XAML:

    <Style TargetType="local:MyLine" 
           x:Key="MyLineStyleKey" x:Name="MyLineStyleName">
        <Setter Property="Fill" Value="Pink"/>
        <Style.Triggers>
            <Trigger Property="IsSelected" Value="true">
                <Setter Property="Fill" Value="Blue" />                    
            </Trigger>
        </Style.Triggers>
    </Style>

1. 稍后，我需要更改Pink 颜色，例如Green，以及所有样式MyLineStyleKey 变为绿色.释放时一条线是粉红色，选中时为蓝色...现在，我需要更改未选中的属性(粉红色到绿色)...，所以这不仅仅是将其设置为其他颜色，触发器(选择>蓝色)) 将不再起作用......这可能吗?怎么样?

1. In a moment, I need to change the Pink color, to, say Green, and all lines with style MyLineStyleKey became Green. A line is Pink when released, and Blue when selected... Now, I needed to change the unselected property(Pink to Green)..., so this is not just setting it to an other color, the trigger (selection>Blue) will not work anymore...Is that possible? How?

是否可以将绑定到样式中的粉红色，例如按钮背景，以反映当前使用的样式颜色?

Is that possible to bind to the Pink color in the Style, say, to a Button background, that will reflect the currently used style color?

对于 1 我试过:

Style s = (Style)this.Resources["MyLineStyleKey"];

(s.Setters[0] as Setter).Value = background;
(s.Setters[1] as Setter).Value = background;

但是发生了异常:

在使用SetterBase"之后(密封)，不可修改.

After a 'SetterBase' is in use (sealed), it cannot be modified.

推荐答案

创建画笔作为资源

<SolidColorBrush x:Key="MyFillBrush" Color="Pink" />

并参考你的风格

<Style x:Key="MyShapeStyle" TargetType="Shape">
    <Setter Property="Fill" Value="{DynamicResource MyFillBrush}" />
</Style>
...
<!-- Then further down you may use it like this -->
<StackPanel Width="100">
    <Rectangle Style="{StaticResource MyShapeStyle}" Height="50" Margin="8" />
    <Rectangle Style="{StaticResource MyShapeStyle}" Height="50" Margin="8" />
    <Ellipse Style="{StaticResource MyShapeStyle}" Height="50" Margin="8" />
    <Button Content="Click to change color" Click="Button_Click" Margin="8" />
</StackPanel>

现在要更改使用MyShapeStyle"样式的所有形状的颜色，您可以从代码隐藏执行以下操作:

Now to change the color of all shapes that use the "MyShapeStyle" style, you can do the following from your code-behind:

private void Button_Click(object sender, RoutedEventArgs e)
{
    Random r = new Random();
    this.Resources["MyFillBrush"] = new SolidColorBrush(Color.FromArgb(
          0xFF, 
          (byte)r.Next(255), 
          (byte)r.Next(255), 
          (byte)r.Next(255)));
}

使这项工作有效的原因是您在样式中使用 DynamicResource 作为画笔引用 - 这告诉 WPF 监视该资源的更改.如果您改用 StaticResource，则不会出现此行为.

The thing that makes this work is the fact that you use a DynamicResource for the brush reference in your style - this tells WPF to monitor that resource for changes. If you use a StaticResource instead, you won't get this behavior.

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