将控件样式与另一个项目设置的全局样式动态合并

Question

我目前面临一个问题。我正在使用我在 codeplex 上找到的 WPF.Themes，它允许我更改应用程序的主题。

所以我导入了项目并让它一切正常，但是对于某些控件，比如我的 treeViewItem，我已经设置了样式，它会覆盖全局样式。

经过研究，我有以下代码，但仍然无法正常工作。

<TreeView Name="_tvTreeView" Grid.Row="1" >
       <TreeView.ItemContainerStyle>
           <Style TargetType="{x:Type TreeViewItem}" BasedOn="{StaticResource {x:Type TreeViewItem}}">
               <EventSetter Event="MouseDoubleClick" Handler="tvTreeView_PreviewMouseDoubleClick"/>
               <EventSetter Event="MouseDown" Handler="tvTreeView_MouseDown"/>
           </Style>
       </TreeView.ItemContainerStyle>
</TreeView>

如果我在主项目的 app.xaml 的合并字典中手动添加资源文件，则基于工作。

但是 WPF.Themes 项目允许我通过这样做来动态更改主题。

  public static void ApplyTheme(this ContentControl control, string theme)
  {
      ResourceDictionary dictionary = ThemeManager.GetThemeResourceDictionary(theme);

      control.Resources.MergedDictionaries.Clear();
      if (dictionary != null)
          control.Resources.MergedDictionaries.Add(dictionary);
  }

拥有上述代码，不会合并全局样式和我的事件设置器。 如果我在 app.xaml 中手动引用主题，则“BasedOn”会启动并工作，但如果我动态设置 mergeDictionaries，“BasedOn”似乎不起作用。

有没有一种方法可以在不将主题添加到 app.xaml 的情况下使其工作。

感谢和问候，

Answer 1

style的BaseOn属性不能用DynamicResource设置，用StaticResource，应用到控件时会被密封。

当全局样式改变时你应该合并样式，试试这些代码：

public class Behavior
{
    #region AutoMergeStyle

    public static readonly DependencyProperty AutoMergeStyleProperty =
        DependencyProperty.RegisterAttached("AutoMergeStyle", typeof(bool), typeof(Behavior),
            new FrameworkPropertyMetadata((bool)false,
                new PropertyChangedCallback(OnAutoMergeStyleChanged)));

    public static bool GetAutoMergeStyle(DependencyObject d)
    {
        return (bool)d.GetValue(AutoMergeStyleProperty);
    }

    public static void SetAutoMergeStyle(DependencyObject d, bool value)
    {
        d.SetValue(AutoMergeStyleProperty, value);
    }

    private static void OnAutoMergeStyleChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (e.OldValue == e.NewValue)
        {
            return;
        }

        Control control = d as Control;
        if (control == null)
        {
            throw new NotSupportedException("AutoMergeStyle can only used in Control");
        }

        if ((bool)e.NewValue)
        {
            Type type = d.GetType();
            control.SetResourceReference(Behavior.BaseOnStyleProperty, type);
        }
        else
        {
            control.ClearValue(Behavior.BaseOnStyleProperty);
        }
    }

    #endregion

    #region BaseOnStyle

    public static readonly DependencyProperty BaseOnStyleProperty =
        DependencyProperty.RegisterAttached("BaseOnStyle", typeof(Style), typeof(Behavior),
            new FrameworkPropertyMetadata((Style)null,
                new PropertyChangedCallback(OnBaseOnStyleChanged)));

    public static Style GetBaseOnStyle(DependencyObject d)
    {
        return (Style)d.GetValue(BaseOnStyleProperty);
    }

    public static void SetBaseOnStyle(DependencyObject d, Style value)
    {
        d.SetValue(BaseOnStyleProperty, value);
    }

    private static void OnBaseOnStyleChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (e.OldValue == e.NewValue)
        {
            return;
        }

        Control control = d as Control;
        if (control == null)
        {
            throw new NotSupportedException("BaseOnStyle can only used in Control");
        }

        Style baseOnStyle = e.NewValue as Style;
        Style originalStyle = GetOriginalStyle(control);
        if (originalStyle == null)
        {
            originalStyle = control.Style;
            SetOriginalStyle(control, originalStyle);
        }
        Style newStyle = originalStyle;

        if (originalStyle.IsSealed)
        {
            newStyle = new Style();
            newStyle.TargetType = originalStyle.TargetType;

            //1. Copy resources, setters, triggers
            newStyle.Resources = originalStyle.Resources;
            foreach (var st in originalStyle.Setters)
            {
                newStyle.Setters.Add(st);
            }
            foreach (var tg in originalStyle.Triggers)
            {
                newStyle.Triggers.Add(tg);
            }

            //2. Set BaseOn Style
            newStyle.BasedOn = baseOnStyle;
        }
        else
        {
            originalStyle.BasedOn = baseOnStyle;
        }

        control.Style = newStyle;
    }

    #endregion

    #region OriginalStyle

    public static readonly DependencyProperty OriginalStyleProperty =
        DependencyProperty.RegisterAttached("OriginalStyle", typeof(Style), typeof(Behavior),
            new FrameworkPropertyMetadata((Style)null));

    public static Style GetOriginalStyle(DependencyObject d)
    {
        return (Style)d.GetValue(OriginalStyleProperty);
    }

    public static void SetOriginalStyle(DependencyObject d, Style value)
    {
        d.SetValue(OriginalStyleProperty, value);
    }

    #endregion
}

将附加属性 AutoMergeStyle 添加到 xaml：

<Style TargetType="{x:Type TreeViewItem}" BasedOn="{StaticResource {x:Type TreeViewItem}}">
               <EventSetter Event="MouseDoubleClick" Handler="tvTreeView_PreviewMouseDoubleClick"/>
               <EventSetter Event="MouseDown" Handler="tvTreeView_MouseDown"/>
               <Setter Property="Behavior.AutoMergeStyle" Property="True"/>
</Style>