用于定义渐变停止颜色 UWP 的主题资源

Question

我正在创建UWP应用程序。我很少有LinearGradientBrushes，其中颜色直接在线性GradientBrush引用中设置为GradientStops。但是，我希望在资源分配中定义一组预定义的颜色，我可以为每个 GradientStop 使用引用，以便更改应用程序的配色方案就像更改 SolidColorBrushes 的值一样：

<!--Resource Dictionary  -->
<ResourceDictionary.ThemeDictionaries>
<ResourceDictionary x:Key="Default">
<SolidColorBrush x:Key="stop1" Color="#FF5A5A5A"/>
<SolidColorBrush x:Key="stop2" Color="#FF222222"/>
</ResourceDictionary>
<ResourceDictionary x:Key="Dark">
<SolidColorBrush x:Key="stop1" Color="Black"/>
<SolidColorBrush x:Key="stop2" Color="White"/>
</ResourceDictionary>
<ResourceDictionary x:Key="HighContrast">
<SolidColorBrush x:Key="stop1" Color="Black"/>
<SolidColorBrush x:Key="stop2" Color="White"/>
</ResourceDictionary>
</ResourceDictionary.ThemeDictionaries>
<!-- control Template-->
<LinearGradientBrush x:Key="gradient">
<GradientStop Color="{Binding Source={Themeresource stop1},Path=Color}" Offset="0"/>
<GradientStop Color="{Binding Source={Themeresource stop2},Path=Color}" Offset="1"/>
</LinearGradientBrush>

它的给出错误，找不到 nam/key stop1

Answer 1

问题是stop1是静态资源而不是Themeresource。因此，我们需要编辑绑定源作为StaticResource。

<LinearGradientBrush x:Key="gradient">
<GradientStop Color="{Binding Source={StaticResource stop1},Path=Color}" Offset="0"/>
<GradientStop Color="{Binding Source={StaticResource stop2},Path=Color}" Offset="1"/>
</LinearGradientBrush>

更新

对于测试，如果我们放在上面ResourceDictionary，它将起作用。

<Page.Resources>
<ResourceDictionary>
<ResourceDictionary.ThemeDictionaries>
<ResourceDictionary x:Key="Default">
<SolidColorBrush x:Key="stop1" Color="#FF5A5A5A"/>
<SolidColorBrush x:Key="stop2" Color="#FF222222"/>
</ResourceDictionary>
<ResourceDictionary x:Key="Dark">
<SolidColorBrush x:Key="stop1" Color="Black"/>
<SolidColorBrush x:Key="stop2" Color="White"/>
</ResourceDictionary>
<ResourceDictionary x:Key="HighContrast">
<SolidColorBrush x:Key="stop1" Color="Black"/>
<SolidColorBrush x:Key="stop2" Color="White"/>
</ResourceDictionary>
</ResourceDictionary.ThemeDictionaries>


<!-- control Template-->
<LinearGradientBrush x:Key="gradient">
<GradientStop Color="{Binding Source={ThemeResource stop1},Path=Color}" Offset="0"/>
<GradientStop Color="{Binding Source={ThemeResource stop2},Path=Color}" Offset="1"/>
</LinearGradientBrush>
</ResourceDictionary>
</Page.Resources>

Answer 2

上述问题可以通过使用绑定来解决

public LinearGradientBrush GradientBrush
{
get { return _GradientBrush; }
set
{
_GradientBrush = value;
RaisePropertyChanged("GradientBrush");
}
}
GradientBrush = GetGradientBrush();
public static LinearGradientBrush GetGradientBrush()
{
var grColor1 = ((SolidColorBrush)Application.Current.Resources["stop1"]).Color;
var grColor2 = ((SolidColorBrush)Application.Current.Resources["stop2"]).Color;
LinearGradientBrush lgBrush = new LinearGradientBrush();
lgBrush.GradientStops.Add(new GradientStop() { Color = grColor1, Offset = 0.1 });
lgBrush.GradientStops.Add(new GradientStop() { Color = grColor2, Offset = 0.9 });
lgBrush.StartPoint = new Point(0, 1);
lgBrush.EndPoint = new Point(1, 0);
return lgBrush;
}
<Grid Background="{Binding GradientBrush}" >