wpf - 动态资源合并不将样式应用于第一个控件

Question

我尝试通过在将控件添加到 UI 的同时将样式资源合并到应用程序资源来为我的自定义控件应用新样式，但新样式并未首次应用于控件。

sample 控制

CustomTextBoxExt.cs

 public class CustomTextBoxExt : TextBox
    {
        static CustomTextBoxExt()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(CustomTextBoxExt), new FrameworkPropertyMetadata(typeof(CustomTextBoxExt)));
        }
    }

默认样式
通用文件

 <Style x:Key="TextBoxExtStyle" TargetType="{x:Type local:CustomTextBoxExt}">
    <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.WindowBrushKey}}" />
    <Setter Property="BorderBrush" Value="Red" />
    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" />
    <Setter Property="BorderThickness" Value="1" />
    <Setter Property="KeyboardNavigation.TabNavigation" Value="None" />
    <Setter Property="HorizontalContentAlignment" Value="Left" />
    <Setter Property="FocusVisualStyle" Value="{x:Null}" />
    <Setter Property="AllowDrop" Value="True" />
    <Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst" />
    <Setter Property="Stylus.IsFlicksEnabled" Value="False" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type local:CustomTextBoxExt}">
                <Border
                    x:Name="border"
                    Background="{TemplateBinding Background}"
                    BorderBrush="{TemplateBinding BorderBrush}"
                    BorderThickness="{TemplateBinding BorderThickness}"
                    SnapsToDevicePixels="True">
                    <ScrollViewer
                        x:Name="PART_ContentHost"
                        Focusable="False"
                        HorizontalScrollBarVisibility="Hidden"
                        VerticalScrollBarVisibility="Hidden" />
                </Border>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsEnabled" Value="False">
                        <Setter TargetName="border" Property="Opacity" Value="0.56" />
                    </Trigger>
                    <Trigger Property="IsMouseOver" Value="True">
                        <Setter TargetName="border" Property="BorderBrush" Value="#FF7EB4EA" />
                    </Trigger>
                    <Trigger Property="IsKeyboardFocused" Value="True">
                        <Setter TargetName="border" Property="BorderBrush" Value="#FF569DE5" />
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
    <Style.Triggers>

        <MultiTrigger>
            <MultiTrigger.Conditions>
                <Condition Property="IsInactiveSelectionHighlightEnabled" Value="True" />
                <Condition Property="IsSelectionActive" Value="False" />
            </MultiTrigger.Conditions>
            <Setter Property="SelectionBrush" Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightBrushKey}}" />
        </MultiTrigger>
    </Style.Triggers>
</Style>
<Style BasedOn="{StaticResource TextBoxExtStyle}" TargetType="{x:Type local:CustomTextBoxExt}" />

自定义主题
TextBoxExtStyle.xaml

<Style x:Key="MaterialTextBoxExtStyle" TargetType="{x:Type local:CustomTextBoxExt}">
    <Setter Property="FocusVisualStyle" Value="{x:Null}" />
    <Setter Property="Foreground" Value="#DD000000" />
    <Setter Property="Background" Value="Transparent" />
    <Setter Property="BorderBrush" Value="#FF9E9E9E" />
    <Setter Property="BorderThickness" Value="0,0,0,1" />
    <Setter Property="FontSize" Value="12" />
    <Setter Property="FontWeight" Value="Normal" />
    <Setter Property="SelectionBrush" Value="#FF0279FF" />
    <Setter Property="AllowDrop" Value="true" />
    <Setter Property="KeyboardNavigation.TabNavigation" Value="None" />
    <Setter Property="HorizontalContentAlignment" Value="Left" />
    <Setter Property="VerticalContentAlignment" Value="Center" />
    <Setter Property="AllowDrop" Value="true" />
    <Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst" />
    <Setter Property="Stylus.IsFlicksEnabled" Value="False" />
    <Setter Property="CaretBrush" Value="#DD000000" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type local:CustomTextBoxExt}">
                <Grid>
                    <Border
                        x:Name="border"
                        Padding="{TemplateBinding Padding}"
                        Background="{TemplateBinding Background}"
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="{TemplateBinding BorderThickness}"
                        SnapsToDevicePixels="true">
                        <ScrollViewer
                            x:Name="PART_ContentHost"
                            Background="Transparent"
                            Focusable="False"
                            HorizontalScrollBarVisibility="Hidden"
                            VerticalScrollBarVisibility="Hidden" />
                    </Border>
                </Grid>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsMouseOver" Value="true">
                        <Setter TargetName="border" Property="BorderBrush" Value="#FF757575" />
                        <Setter TargetName="border" Property="Background" Value="Transparent" />
                        <Setter Property="Foreground" Value="#DD000000" />
                        <Setter Property="CaretBrush" Value="#DD000000" />
                    </Trigger>
                    <Trigger Property="IsKeyboardFocused" Value="true">
                        <Setter TargetName="border" Property="BorderBrush" Value="#FF0279FF" />
                        <Setter Property="BorderThickness" Value="0,0,0,2" />
                        <Setter Property="Padding" Value="0,0,0,-1" />
                    </Trigger>
                    <Trigger Property="IsEnabled" Value="False">
                        <Setter TargetName="border" Property="Background" Value="Transparent" />
                        <Setter TargetName="border" Property="BorderBrush" Value="#FFE0E0E0" />
                        <Setter Property="Foreground" Value="#60000000" />
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

<Style BasedOn="{StaticResource MaterialTextBoxExtStyle}" TargetType="{x:Type local:CustomTextBoxExt}" />

并使用附加属性，尝试从默认样式更改样式，

public class SkinExt
{
    public static string GetTheme(DependencyObject obj)
    {
        return (string)obj.GetValue(ThemeProperty);
    }

    public static void SetTheme(DependencyObject obj, string value)
    {
        obj.SetValue(ThemeProperty, value);
    }

    // Using a DependencyProperty as the backing store for Theme.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty ThemeProperty =
        DependencyProperty.RegisterAttached("Theme", typeof(string), typeof(SkinExt), new FrameworkPropertyMetadata(string.Empty, FrameworkPropertyMetadataOptions.Inherits, new PropertyChangedCallback(OnVisualStyleChanged)));


    private static void OnVisualStyleChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (e.NewValue != e.OldValue && !string.IsNullOrEmpty(e.NewValue.ToString()) /*&& d is FrameworkElement && (d as FrameworkElement).IsLoaded*/)
        {
            SkinExt.ApplyTheme(d, e.NewValue.ToString());
        }
    }

    internal static void ApplyTheme(DependencyObject obj, string style)
    {
        Type itemType = obj.GetType();

        List<string> styles = GetDictionaries(obj.GetType().Name.ToString(), style);

        if (styles != null && styles.Count > 0)
        {
            foreach (var path in styles)
            {
                var rdict = new ResourceDictionary() { Source = new Uri(path, UriKind.RelativeOrAbsolute) };
                bool alreadyExist = false;
                foreach (var dictionaryFiles in Application.Current.Resources.MergedDictionaries)
                {
                    if (dictionaryFiles.Source.OriginalString.Contains(path))
                    {
                        alreadyExist = true;
                        break;
                    }
                }

                if (!alreadyExist)
                {
                    Application.Current.Resources.MergedDictionaries.Add(rdict);
                    Console.WriteLine(path);
                }
            }

        }
    }

    internal static List<string> GetDictionaries(String type, string style)
    {
        List<string> styles = new List<string>();
        #region Switch

        switch (type)
        {
            case "CustomTextBoxExt":
                styles.Add("/TextBoxExt;component/TextBoxExt/TextBoxExtStyle.xaml");
                break;
            case "ButtonExt":
                styles.Add("/TextBoxExt;component/ButtonExt/ButtonExtStyle.xaml");
                break;
            case "Label":
                styles.Add("/TextBoxExt;component/LabelStyle.xaml");
                break;
        }

        # endregion

        return styles;
    }

}

环境

local:SkinExt.Theme="Material" 

在主窗口/网格中直接添加子项时按预期工作。但是，当使用下面的lazyextension 样式时不起作用。

public static class LazyLoadExtensions
{
    public static LazyUIElementCollection GetLazyChildrens(DependencyObject obj)
    {
        return (LazyUIElementCollection)obj.GetValue(LazyChildrensProperty);
    }

    public static void SetLazyChildrens(DependencyObject obj, LazyUIElementCollection value)
    {
        obj.SetValue(LazyChildrensProperty, value);
    }

    public static readonly DependencyProperty LazyChildrensProperty =
        DependencyProperty.RegisterAttached("LazyChildrens", typeof(LazyUIElementCollection), typeof(LazyLoadExtensions), new PropertyMetadata(OnLazyChildrensChanged));

    private static void OnLazyChildrensChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var wrapPanel = d as WrapPanel;
        var childrens = LazyLoadExtensions.GetLazyChildrens(wrapPanel);
        for (int i = 0; i < childrens.Count; i++)
        {
            var child = childrens[i];

                wrapPanel.Children.Add(child);
        }

    }
}

public class LazyUIElementCollection : List<UIElement>
{
    public LazyUIElementCollection()
    {

    }
}

作品

 <Grid local:SkinExt.Theme="Material">
    <WrapPanel x:Name="wrapPanel">
        <!--<local:LazyLoadExtensions.LazyChildrens>-->
        <!--<local:LazyUIElementCollection>-->
        <StackPanel Margin="10">
            <TextBlock Margin="0,0,0,8" Text="MS Label" />
            <Label
                Width="200"
                Height="25"
                Content="Material" />
        </StackPanel>
        <StackPanel Margin="10">
            <TextBlock Margin="0,0,0,8" Text="Custom TextBox" />
            <local:CustomTextBoxExt
                Width="200"
                Height="25"
                Text="Material" />
        </StackPanel>
        <!--</local:LazyUIElementCollection>-->
        <!--</local:LazyLoadExtensions.LazyChildrens>-->
    </WrapPanel>
</Grid>

不工作

<Grid local:SkinExt.Theme="Material">
    <WrapPanel x:Name="wrapPanel">
        <local:LazyLoadExtensions.LazyChildrens>
            <local:LazyUIElementCollection>
                <StackPanel Margin="10">
                    <TextBlock Margin="0,0,0,8" Text="MS Label" />
                    <Label
                        Width="200"
                        Height="25"
                        Content="Material" />
                </StackPanel>
                <StackPanel Margin="10">
                    <TextBlock Margin="0,0,0,8" Text="Custom TextBox" />
                    <local:CustomTextBoxExt
                        Width="200"
                        Height="25"
                        Text="Material" />
                </StackPanel>
            </local:LazyUIElementCollection>
        </local:LazyLoadExtensions.LazyChildrens>
    </WrapPanel>
</Grid>

适用于第二项

样式正确应用于第二个 customtextboxext

<Grid local:SkinExt.Theme="Material">
    <WrapPanel x:Name="wrapPanel">
        <local:LazyLoadExtensions.LazyChildrens>
            <local:LazyUIElementCollection>
                <StackPanel Margin="10">
                    <TextBlock Margin="0,0,0,8" Text="MS Label" />
                    <Label
                        Width="200"
                        Height="25"
                        Content="Material" />
                </StackPanel>
                <StackPanel Margin="10">
                    <TextBlock Margin="0,0,0,8" Text="Custom TextBox" />
                    <local:CustomTextBoxExt
                        Width="200"
                        Height="25"
                        Text="Material" />
                    <local:CustomTextBoxExt
                        Width="200"
                        Height="25"
                        Text="Material" />
                </StackPanel>
            </local:LazyUIElementCollection>
        </local:LazyLoadExtensions.LazyChildrens>
    </WrapPanel>
</Grid>

可重现样本: https://drive.google.com/open?id=1iB9sY90T7aRaaRTzVc1EvE2qFU13fHG7

检查上面的样本，让我知道你的想法

Answer 1

很酷的项目!

我不确定为什么会出现这个问题，但这似乎是一个时间问题。

我找到了以下解决方法:
在 LazyLoadExtensions 中:

private static void OnLazyChildrensChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var wrapPanel = d as WrapPanel;
        var childrens = LazyLoadExtensions.GetLazyChildrens(wrapPanel);
        for (int i = 0; i < childrens.Count; i++)
        {
            var child = childrens[i];

            //The dictionaries containing the styles are added
            SkinExt.SetTheme(child, SkinExt.GetTheme(wrapPanel));
            wrapPanel.Children.Add(child);
        }

    }

这样，包含样式的字典会在添加子项和正确应用样式之前合并。

编辑:
由于您无法更改 LazyLoadExtensions 类:

在 SkinExt 类中:

internal static void ApplyTheme(DependencyObject obj, string style)
    {
        Type itemType = obj.GetType();

        List<string> styles = GetDictionaries(obj.GetType().Name.ToString(), style);

        if (styles != null && styles.Count > 0)
        {
            foreach (var path in styles)
            {
                var rdict = new ResourceDictionary() { Source = new Uri(path, UriKind.RelativeOrAbsolute) };
                bool alreadyExist = false;
                foreach (var dictionaryFiles in Application.Current.Resources.MergedDictionaries)
                {
                    if (dictionaryFiles.Source.OriginalString.Contains(path))
                    {
                        alreadyExist = true;
                        break;
                    }
                }

                if (!alreadyExist)
                {
                    Application.Current.Resources.MergedDictionaries.Add(rdict);
                    if (obj is FrameworkElement frameworkElement && frameworkElement.IsInitialized)
                    {
                        //The style won't be applied automaticaly
                        frameworkElement.Style = rdict.Values.OfType<Style>().First(s => s.TargetType == itemType);
                    }
                    else
                    {
                        //Nothing to do, style will be applied automaticaly
                    }
                    Console.WriteLine(path);
                }
            }

        }
    }

如果 IsInitialized 属性为 true，则不会应用添加的 ressourceDictionnary 中的样式，您可以在调试器中检查它。

https://docs.microsoft.com/en-gb/dotnet/api/system.windows.frameworkelement.isinitialized?view=netcore-3.1#System_Windows_FrameworkElement_IsInitialized