ListViewItem样式适用于App.xaml，但不适用于用户控件xaml

Question

我编写了自己的用户控件，其中包含一个列表视图，并且其 ItemsSource 是设置运行时。我想从用户控件 xaml 设置我自己的 ListViewItem 样式，但我无法让它工作，无论如何，从 App.xaml 设置它完美无缺，所以我想知道为什么？

用户控件 xaml 如下所示：

<UserControl x:Class="LogManagerWPF.LogManager"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:local="clr-namespace:LogManagerWPF"
             mc:Ignorable="d" 
             d:DesignHeight="192" d:DesignWidth="400"
             DataContext="{Binding RelativeSource={RelativeSource Self}}">
    <UserControl.Resources>
        <DataTemplate x:Key="DisplayImage">
            <Image Source="{Binding ImageIcon}" Width="16" Height="16"/>
        </DataTemplate>
        <Style TargetType="{x:Type ListViewItem}">
            <Setter Property="HorizontalContentAlignment" Value="Stretch" />
            <Setter Property="VerticalContentAlignment" Value="Center" />
        </Style>
    </UserControl.Resources>
    <ListView Margin="0" x:Name="m_lvLog" ScrollViewer.VerticalScrollBarVisibility="Auto" ScrollViewer.HorizontalScrollBarVisibility="Auto" ContextMenuOpening="m_lvLog_ContextMenuOpening" SelectionChanged="m_lvLog_SelectionChanged">
        <ListView.Resources>
            <!-- Windows 7 -->
            <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="{Binding SelectedRowBackColor, RelativeSource={RelativeSource FindAncestor, AncestorType=UserControl}}" />
            <SolidColorBrush x:Key="{x:Static SystemColors.ActiveBorderBrushKey}" Color="{Binding SelectedRowBackColor, RelativeSource={RelativeSource FindAncestor, AncestorType=UserControl}}" />
            <!-- Windows 10 -->
            <Style TargetType="{x:Type ListViewItem}">
                <Style.Triggers>
                    <Trigger Property="IsSelected" Value="True">
                        <Setter Property="Background">
                            <Setter.Value>
                                <SolidColorBrush Color="{Binding SelectedRowBackColor, RelativeSource={RelativeSource FindAncestor, AncestorType=UserControl}}"></SolidColorBrush>
                            </Setter.Value>
                        </Setter>
                        <Setter Property="BorderBrush">
                            <Setter.Value>
                                <SolidColorBrush Color="{Binding SelectedRowBackColor, RelativeSource={RelativeSource FindAncestor, AncestorType=UserControl}}"></SolidColorBrush>
                            </Setter.Value>
                        </Setter>
                    </Trigger>
                </Style.Triggers>
            </Style>
        </ListView.Resources>
        <ListView.View>
            <GridView x:Name="m_gvLog" AllowsColumnReorder="False">
                <GridViewColumn x:Name="m_icon" Width="28" Header="" CellTemplate="{StaticResource DisplayImage}"/>
                <GridViewColumn x:Name="m_time" Width="Auto" Header="Timestamp" DisplayMemberBinding="{Binding Timestamp}">
                    <GridViewColumn.HeaderContainerStyle>
                        <Style TargetType="{x:Type GridViewColumnHeader}">
                            <Setter Property="Foreground" Value="#FF042271" />
                            <Setter Property="HorizontalContentAlignment" Value="Left" />
                            <Setter Property="Padding" Value="10,0,0,0" />
                        </Style>
                    </GridViewColumn.HeaderContainerStyle>
                </GridViewColumn>
                <GridViewColumn x:Name="m_messages" Width="100" Header="Message" DisplayMemberBinding="{Binding Message}">
                    <GridViewColumn.HeaderContainerStyle>
                        <Style TargetType="{x:Type GridViewColumnHeader}">
                            <Setter Property="Foreground" Value="#FF042271" />
                            <Setter Property="HorizontalContentAlignment" Value="Left" />
                            <Setter Property="Padding" Value="10,0,0,0" />
                        </Style>
                    </GridViewColumn.HeaderContainerStyle>
                </GridViewColumn>
            </GridView>
        </ListView.View>
        <ListView.ContextMenu>
            <ContextMenu x:Name="m_contextMenu">
                <MenuItem x:Name="m_menuAutoScroll" Header="Autoscroll" Click="m_menuAutoScroll_Click" IsCheckable="True" />
                <MenuItem x:Name="m_menuClear" Header="Clear Log" Click="m_menuClear_Click"/>
                <MenuItem x:Name="m_menuCopy" Header="Copy to Clipboard" Click="m_menuCopy_Click"/>
                <MenuItem x:Name="m_menuOpenLog" Header="Open Log" Click="m_menuOpenLog_Click"/>
                <MenuItem x:Name="m_menuHorizontalScrollBarVisibility" Header="Set Horizontal ScrollBar Visibility">
                    <MenuItem x:Name="m_menuHorizontalScrollBarEnabled" Header="Enabled" Click="m_menuHorizontalScrollBarEnabled_Click" IsCheckable="True"/>
                    <MenuItem x:Name="m_menuHorizontalScrollBarDisabled" Header="Disabled" Click="m_menuHorizontalScrollBarDisabled_Click" IsCheckable="True"/>
                </MenuItem>
                <MenuItem x:Name="m_menuVerbosity" Header="Set Verbosity">
                    <MenuItem x:Name="m_menuVerbosityLow" Header="Low" Click="m_menuVerbosityLow_Click" IsCheckable="True"/>
                    <MenuItem x:Name="m_menuVerbosityStandard" Header="Standard" Click="m_menuVerbosityStandard_Click" IsCheckable="True"/>
                    <MenuItem x:Name="m_menuVerbosityHigh" Header="High" Click="m_menuVerbosityHigh_Click" IsCheckable="True"/>
                    <MenuItem x:Name="m_menuVerbosityDebug" Header="Debug" Click="m_menuVerbosityDebug_Click" IsCheckable="True"/>
                </MenuItem>
                <MenuItem x:Name="m_menuSeverityFilter" Header="Set Severity Filter">
                    <MenuItem x:Name="m_menuSeverityFilterDebug" Header="Debug" Checked="m_menuSeverityFilterDebug_CheckedChanged" Unchecked="m_menuSeverityFilterDebug_CheckedChanged" IsCheckable="True" StaysOpenOnClick="True"/>
                    <MenuItem x:Name="m_menuSeverityFilterInformation" Header="Information" Checked="m_menuSeverityFilterInformation_CheckedChanged" Unchecked="m_menuSeverityFilterInformation_CheckedChanged" IsCheckable="True" StaysOpenOnClick="True"/>
                    <MenuItem x:Name="m_menuSeverityFilterWarning" Header="Warning" Checked="m_menuSeverityFilterWarning_CheckedChanged" Unchecked="m_menuSeverityFilterWarning_CheckedChanged" IsCheckable="True" StaysOpenOnClick="True"/>
                    <MenuItem x:Name="m_menuSeverityFilterError" Header="Error" Checked="m_menuSeverityFilterError_CheckedChanged" Unchecked="m_menuSeverityFilterError_CheckedChanged" IsCheckable="True" StaysOpenOnClick="True"/>
                    <Separator/>
                    <MenuItem x:Name="m_menuSeverityFilterAll" Header="All" Click="m_menuSeverityFilterAll_Click" StaysOpenOnClick="True"/>
                    <MenuItem x:Name="m_menuSeverityFilterNone" Header="None" Click="m_menuSeverityFilterNone_Click" StaysOpenOnClick="True"/>
                </MenuItem>
                <MenuItem x:Name="m_menuContentFilter" Header="Set Content Filter">
                    <MenuItem x:Name="m_menuContentFilterSet">
                        <MenuItem.Header>
                            <StackPanel Orientation="Horizontal">
                                <Label Content="Set" Padding="0"/>
                                <TextBox x:Name="m_menuContentFilterString" Width="150" Padding="0" Margin="10,0,0,0" VerticalContentAlignment="Center" LostFocus="m_menuContentFilterString_LostFocus"/>
                            </StackPanel>
                        </MenuItem.Header>
                    </MenuItem>
                    <MenuItem x:Name="m_menuContentFilterClear" Header="Clear" Click="m_menuContentFilterClear_Click"/>
                </MenuItem>
            </ContextMenu>
        </ListView.ContextMenu>
    </ListView>
</UserControl>

我想应用的样式是这样的:

<Application x:Class="LogManagerWpf_Tester.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             StartupUri="MainWindow.xaml">
    <Application.Resources>
        <Style TargetType="{x:Type ListViewItem}">
            <Setter Property="HorizontalContentAlignment" Value="Stretch" />
            <Setter Property="VerticalContentAlignment" Value="Center" />
        </Style>
    </Application.Resources>
</Application>

我知道当从用户控件本身执行样式时，不会应用该样式，因为在输出窗口中，我看到添加的每个ListViewItem都出现以下错误，而当从App.xaml应用样式时，这些错误不会显示：

System.Windows.Data 错误： 4 ： 找不到引用“RelativeSource FindAncestor， AncestorType='System.Windows.Controls.ItemsControl'， AncestorLevel='1'”进行绑定的源。绑定表达式：路径=水平内容对齐;数据项=空;目标元素是“列表视图项”（名称=“）;目标属性为“水平内容对齐”（类型为“水平对齐”）

系统。Windows.Data错误:4:找不到引用为“RelativeSource FindAncestor，ancestor type =”System的绑定的源。Windows.Controls.ItemsControl '，AncestorLevel='1 ' '。binding expression:Path = VerticalContentAlignment；DataItem = null目标元素是“ListViewItem”(名称=“”)；目标属性为“VerticalContentAlignment”(类型为“VerticalAlignment”)

Answer 1

我不喜欢编辑一个应用程序的App.xaml文件来放置一个修复用户控件问题的样式，因为那样我将不得不编辑使用这种控件的每个应用程序。幸运的是，我找到了一个放置在用户控件构造器中的变通方法，它允许我在不编辑应用程序xaml文件的情况下解决这个问题:

Style listViewItemStyle = new Style(typeof(ListViewItem));
listViewItemStyle.Setters.Add(new Setter(ListViewItem.HorizontalContentAlignmentProperty, HorizontalAlignment.Stretch));
listViewItemStyle.Setters.Add(new Setter(ListViewItem.VerticalContentAlignmentProperty, VerticalAlignment.Center));

if (!Application.Current.Resources.Contains(typeof(ListViewItem)))
{
    Application.Current.Resources.Add(typeof(ListViewItem), listViewItemStyle);
}

虽然上面的代码有效，但我想知道为什么我不能直接从用户控件 xaml 获得所需的结果。