基于风格的DynamicResourceOn

Question

构建具有自定义“高对比度”主题的应用程序，用于户外使用，可在运行期间打开和关闭。这是通过合并和取消合并包含类似下面的样式资源字典罚款...

<Style x:Key="{x:Type MenuItem}" TargetType="{x:Type MenuItem}"> 
    <Setter Property="OverridesDefaultStyle" Value="true"/> 
    <Setter Property="FocusVisualStyle" Value="{x:Null}"/> 
    <Setter Property="Template" Value="{StaticResource Theme_MenuItemTemplate}"/> 
</Style> 

这当一个菜单项的使用不指定样式的伟大工程。这对于许多情况来说并不现实，因为没有方式来绑定没有样式的ItemsSource生成的子项。例如：

<ContextMenu.ItemContainerStyle> 
    <Style TargetType="MenuItem"> 
     <Setter Property="Header" Value="{Binding Path=Name}"/> 
     <Setter Property="IsCheckable" Value="True"/> 
     <Setter Property="IsChecked" Value="{Binding Path=Checked}"/> 
     <EventSetter Event="Checked" Handler="HistoryItem_Checked"/> 
    </Style> 
</ContextMenu.ItemContainerStyle> 

每隔后在计算器上说，你只需要做到这一点...

<Style TargetType="MenuItem" BasedOn="{StaticResource {x:Type MenuItem}}"> 
    <!-- Your overrides --> 
</Style> 

但是，这并不对我的情况下工作，因为我的支持算法FMP能够而且将会在运行时改变（当然，你不能在BasedOn属性上使用DynamicResource扩展）。在我的应用程序中执行此操作时，会导致控件在控件加载时覆盖其样式，而每个其他控件在没有重新加载的情况下正确切换时会导致控件被阻塞。

所以我的问题......

有没有办法让DynamicResource扩展支持算法FMP工作或有另一种方法/帮闲我可以实现得到这个工作？

Answer 1

终于想通了一个DynamicResouce为Style.BasedOn使用AttachedDependencyProperty的解决方案。

这里是ItemsControl.ItemContainerStyle修复（可以很容易地修改，以改变FrameworkElement.Style）

public class DynamicContainerStyle 
{ 
    public static Style GetBaseStyle(DependencyObject obj) 
    { 
     return (Style)obj.GetValue(BaseStyleProperty); 
    } 

    public static void SetBaseStyle(DependencyObject obj, Style value) 
    { 
     obj.SetValue(BaseStyleProperty, value); 
    } 

    // Using a DependencyProperty as the backing store for BaseStyle. This enables animation, styling, binding, etc... 
    public static readonly DependencyProperty BaseStyleProperty = 
     DependencyProperty.RegisterAttached("BaseStyle", typeof(Style), typeof(DynamicContainerStyle), new UIPropertyMetadata(DynamicContainerStyle.StylesChanged)); 

    public static Style GetDerivedStyle(DependencyObject obj) 
    { 
     return (Style)obj.GetValue(DerivedStyleProperty); 
    } 

    public static void SetDerivedStyle(DependencyObject obj, Style value) 
    { 
     obj.SetValue(DerivedStyleProperty, value); 
    } 

    // Using a DependencyProperty as the backing store for DerivedStyle. This enables animation, styling, binding, etc... 
    public static readonly DependencyProperty DerivedStyleProperty = 
     DependencyProperty.RegisterAttached("DerivedStyle", typeof(Style), typeof(DynamicContainerStyle), new UIPropertyMetadata(DynamicContainerStyle.StylesChanged)); 

    private static void StylesChanged(DependencyObject target, DependencyPropertyChangedEventArgs e) 
    { 
     if (!typeof(System.Windows.Controls.ItemsControl).IsAssignableFrom(target.GetType())) 
      throw new InvalidCastException("Target must be ItemsControl"); 

     var Element = (System.Windows.Controls.ItemsControl)target; 

     var Styles = new List<Style>(); 

     var BaseStyle = GetBaseStyle(target); 

     if (BaseStyle != null) 
      Styles.Add(BaseStyle); 

     var DerivedStyle = GetDerivedStyle(target); 

     if (DerivedStyle != null) 
      Styles.Add(DerivedStyle); 

     Element.ItemContainerStyle = MergeStyles(Styles); 
    } 

    private static Style MergeStyles(ICollection<Style> Styles) 
    { 
     var NewStyle = new Style(); 

     foreach (var Style in Styles) 
     { 
      foreach (var Setter in Style.Setters) 
       NewStyle.Setters.Add(Setter); 

      foreach (var Trigger in Style.Triggers) 
       NewStyle.Triggers.Add(Trigger); 
     } 

     return NewStyle; 
    } 
} 

而且这里有一个例子...

<!-- xmlns:ap points to the namespace where DynamicContainerStyle class lives --> 
<MenuItem Header="Recent" 
    ItemsSource="{Binding Path=RecentFiles}" 
    IsEnabled="{Binding RelativeSource={RelativeSource Self}, Path=HasItems}" 
    ap:DynamicContainerStyle.BaseStyle="{DynamicResource {x:Type MenuItem}}"> 
    <ap:DynamicContainerStyle.DerivedStyle> 
     <Style TargetType="MenuItem"> 
      <EventSetter Event="Click" Handler="RecentFile_Clicked"/> 
     </Style> 
    </ap:DynamicContainerStyle.DerivedStyle> 
    <MenuItem.ItemTemplate> 
     <DataTemplate> 
      <TextBlock Text="{Binding}"/> 
     </DataTemplate> 
    </MenuItem.ItemTemplate> 
</MenuItem> 

下面是修改后的版本，设置了FrameworkElement.Style而不是在我回答另一篇文章： Setting a local implicit style different from theme-style/alternative to BasedOn DynamicResource

Answer 2

您的样式应该位于UIElement.Resources标记中。这可以动态清除并重新填充。

我做同样的事情，但没有复杂的是这样的：

MobileApp.Get().Resources.MergedDictionaries.Clear(); 

Uri uri = new Uri("/Resources/DayModeButton.xaml", UriKind.Relative); 
ResourceDictionary resDict = Application.LoadComponent(uri) as ResourceDictionary; 

resDict["SelectedColor"] = selectedColor; //change an attribute of resdict 

MobileApp.Get().Resources.MergedDictionaries.Add(resDict); 

Answer 3

我有一个微小的imp对于NtscCobalts的回答：

#region Type-specific function (FrameworkElement) 
    private static void StylesChanged(DependencyObject target, DependencyPropertyChangedEventArgs e) 
    { 
     var mergedStyles = GetMergedStyles<FrameworkElement>(target, GetBaseStyle(target), GetDerivedStyle(target)); // NOTE: change type on copy 

     var element = (FrameworkElement)target; // NOTE: change type on copy 

     element.Style = mergedStyles; 
    } 
    #endregion Type-specific function (FrameworkElement) 


    #region Reused-function 
    public static Style GetMergedStyles<T>(DependencyObject target, Style baseStyle, Style derivedStyle) where T : DependencyObject 
    { 
     if (!(target is T)) throw new InvalidCastException("Target must be " + typeof(T)); 

     if (derivedStyle == null) return baseStyle; 
     if (baseStyle == null) return derivedStyle; 

     var newStyle = new Style { BasedOn = baseStyle, TargetType = derivedStyle.TargetType }; 
     foreach (var setter in derivedStyle.Setters) newStyle.Setters.Add(setter); 
     foreach (var trigger in derivedStyle.Triggers) newStyle.Triggers.Add(trigger); 
     return newStyle; 

    } 
    #endregion Reused-function 

您会发现，创建新样式时可以简单地设置基础样式。这样，基本样式中的基本样式自动处于层次结构中。