WINUI3/UWP中如何设置DataGrid行鼠标悬停时背景透明？

推荐方案：通过XAML样式修改视觉状态 #

无需编写后台代码，直接修改DataGridRow的样式覆盖鼠标悬停（PointerOver）状态的背景，这是最符合WINUI设计模式的方式，还能避免反射带来的版本兼容性问题：

<Page.Resources>
    <!-- 引用Community Toolkit命名空间 -->
    <xmlns:controls="using:CommunityToolkit.WinUI.UI.Controls"/>

    <Style TargetType="controls:DataGridRow">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="controls:DataGridRow">
                    <Grid>
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="CommonStates">
                                <VisualState x:Name="Normal"/>
                                <!-- 鼠标悬停状态：设置背景为透明 -->
                                <VisualState x:Name="PointerOver">
                                    <VisualState.Setters>
                                        <Setter Target="RootGrid.Background" Value="Transparent"/>
                                    </VisualState.Setters>
                                </VisualState>
                                <!-- 可选：同时修改选中行的背景为透明 -->
                                <VisualState x:Name="Selected">
                                    <VisualState.Setters>
                                        <Setter Target="RootGrid.Background" Value="Transparent"/>
                                    </VisualState.Setters>
                                </VisualState>
                                <VisualState x:Name="SelectedUnfocused">
                                    <VisualState.Setters>
                                        <Setter Target="RootGrid.Background" Value="Transparent"/>
                                    </VisualState.Setters>
                                </VisualState>
                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                        <Grid x:Name="RootGrid" Background="{TemplateBinding Background}">
                            <ContentPresenter Content="{TemplateBinding Content}"/>
                        </Grid>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</Page.Resources>

代码方式（修正版） #

如果坚持用后台代码实现，需要修正原代码的核心问题，确保只修改当前悬停行的背景，并正确处理状态恢复：

using CommunityToolkit.WinUI.UI.Controls;
using Microsoft.UI.Xaml;
using Microsoft.UI.Xaml.Input;
using Microsoft.UI.Xaml.Controls;

public DataGridControl()
{
    this.Loaded += DataGridControl_Loaded;
}

private void DataGridControl_Loaded(object sender, RoutedEventArgs e)
{
    if (sender is not DataGrid dataGrid) return;

    // 监听行容器生成事件，确保新添加的行也能绑定事件
    dataGrid.ItemContainerGenerator.ItemsChanged += ItemContainerGenerator_ItemsChanged;
    // 初始化已存在的行事件绑定
    BindRowEvents(dataGrid);
}

private void ItemContainerGenerator_ItemsChanged(object? sender, ItemsChangedEventArgs e)
{
    if (sender is ItemContainerGenerator generator && generator.ContainerFromIndex(0) is DataGridRow row)
    {
        var dataGrid = row.FindParent<DataGrid>();
        BindRowEvents(dataGrid);
    }
}

private void BindRowEvents(DataGrid dataGrid)
{
    foreach (var row in dataGrid.FindDescendants().OfType<DataGridRow>())
    {
        // 避免重复绑定事件
        row.PointerEntered -= Row_PointerEntered;
        row.PointerEntered += Row_PointerEntered;
        row.PointerExited -= Row_PointerExited;
        row.PointerExited += Row_PointerExited;
    }
}

private void Row_PointerEntered(object sender, PointerRoutedEventArgs e)
{
    if (sender is DataGridRow row && !row.IsSelected)
    {
        row.Background = new SolidColorBrush(Windows.UI.Colors.Transparent);
    }
}

private void Row_PointerExited(object sender, PointerRoutedEventArgs e)
{
    if (sender is DataGridRow row && !row.IsSelected)
    {
        // 恢复为DataGrid的背景色，或自定义默认背景
        row.Background = this.Background;
    }
}

原代码的问题说明 #

• 监听整个DataGrid的PointerEntered事件会导致鼠标进入时所有行背景被修改，而非当前悬停的行
• 错误使用反射访问IsSelected，该属性是DataGridRow的公开成员，可直接调用
• 缺少PointerExited事件处理，鼠标离开行后无法恢复默认背景

内容的提问来源于stack exchange，提问作者Ragavan