WPF - XAML - DataGridRow 样式触发器 IsMouseOver 工具提示数据绑定

Question

我正在尝试获得一个工具提示，以在鼠标悬停在 WPF 中的 DataGrid 内的一行时显示图像。

这是 RowStyle 的 XAML 的 sn-p：

            <DataGrid.RowStyle>
            <Style TargetType="DataGridRow" >
                <Style.Triggers>
                    <DataTrigger Binding="{Binding Path=CNIsOnline,UpdateSourceTrigger=PropertyChanged}" Value="False">
                        <Setter Property="Background" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}},Path=DataContext.OfflineColor,UpdateSourceTrigger=PropertyChanged}"></Setter>
                    </DataTrigger>
                    <DataTrigger Binding="{Binding Path=CNIsOnline,UpdateSourceTrigger=PropertyChanged}" Value="True">
                        <Setter Property="Background" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}},Path=DataContext.OnlineColor,UpdateSourceTrigger=PropertyChanged}"></Setter>
                    </DataTrigger>
                    <DataTrigger Binding="{Binding Path=CNIsOnline,UpdateSourceTrigger=PropertyChanged}" Value="{x:Null}">
                        <Setter Property="Background" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}},Path=DataContext.UnknownColor,UpdateSourceTrigger=PropertyChanged}"></Setter>
                    </DataTrigger>
                    <Trigger Property="IsMouseOver" Value="True">
                        <Setter Property="DataContext" Value="{Binding PlacementTarget.DataContext, RelativeSource={RelativeSource Self}}"/>
                        <Setter Property="ToolTip">
                            <Setter.Value>
                                <Image Height="50" Width="50" Source="{Binding userimg}"/>
                            </Setter.Value>
                        </Setter>
                    </Trigger>
                </Style.Triggers>
            </Style>
        </DataGrid.RowStyle>

我知道 userimg 设置正确，因为如果我采取这一行：

<Image Height="50" Width="50" Source="{Binding userimg}"/>

然后将它放在我的 XAML 中的其他位置，我会看到图像。如果我将 userimg（它只是一个 PNG 路径的字符串）更改为硬编码路径，它似乎可以工作，所以我知道这是一个数据上下文问题。

我已经尝试了几件事，包括：this、this、this 和 this，但我仍然难以通过使用数据绑定来显示此图像。

我也试过了，也没有运气：

<Setter Property="ToolTip">
<Setter.Value>
    <Image Height="50" Width="50" Source={Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}},Path=DataContext.userimg,UpdateSourceTrigger=PropertyChanged}"/>
</Setter.Value>

这些是我尝试查看工具提示时出现的错误：

System.Windows.Data Error: 40 : BindingExpression path error: 'userimg' property not found on 'object' ''DataRowView' (HashCode=6587426)'. BindingExpression:Path=userimg; DataItem='DataRowView' (HashCode=6587426); target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource')

System.Windows.Data Information: 20 : BindingExpression cannot retrieve value due to missing information. BindingExpression:Path=userimg; DataItem='DataRowView' (HashCode=6587426); target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource')

System.Windows.Data Information: 21 : BindingExpression cannot retrieve value from null data item. This could happen when binding is detached or when binding to a Nullable type that has no value. BindingExpression:Path=userimg; DataItem='DataRowView' (HashCode=6587426); target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource')

System.Windows.Data Information: 10 : Cannot retrieve value using the binding and no valid fallback value exists; using default instead. BindingExpression:Path=userimg; DataItem='DataRowView' (HashCode=6587426); target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource')

System.Windows.Data Information: 41 : BindingExpression path error: 'userimg' property not found for 'object' because data item is null.  This could happen because the data provider has not produced any data yet. BindingExpression:Path=userimg; DataItem=null; target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource')

System.Windows.Data Information: 20 : BindingExpression cannot retrieve value due to missing information. BindingExpression:Path=userimg; DataItem=null; target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource')

System.Windows.Data Information: 21 : BindingExpression cannot retrieve value from null data item. This could happen when binding is detached or when binding to a Nullable type that has no value. BindingExpression:Path=userimg; DataItem=null; target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource')

System.Windows.Data Information: 10 : Cannot retrieve value using the binding and no valid fallback value exists; using default instead. BindingExpression:Path=userimg; DataItem=null; target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource')

有人可以帮忙吗，不能再松开头发了...

更新

感谢安迪的回复，这是我整个数据网格的 sn-p：

        <DataGrid Grid.Row="1" Grid.ColumnSpan="187"  Name="DG1" Background="Transparent" Foreground="{Binding MyForegroundColor}" BorderThickness="0" HeadersVisibility="Column" CanUserAddRows="False" IsReadOnly="True" Opacity="1" SelectionMode="Single" AutoGenerateColumns="True">
        <DataGrid.Resources>
            <Style TargetType="ScrollBar">
                <Setter Property="Opacity" Value=".3" />
            </Style>
            <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="{Binding MyAccentColor,Converter={StaticResource ColorToSolidColorBrush_ValueConverter}}"/>
            <SolidColorBrush x:Key="{x:Static SystemColors.HighlightTextBrushKey}" Color="{Binding MyForegroundColor,Converter={StaticResource ColorToSolidColorBrush_ValueConverter}}"/>
            <SolidColorBrush x:Key="{x:Static SystemColors.InactiveSelectionHighlightBrushKey}"  Color="{Binding MyAccentColor,Converter={StaticResource ColorToSolidColorBrush_ValueConverter}}"/>
            <SolidColorBrush x:Key="{x:Static SystemColors.InactiveSelectionHighlightTextBrushKey}" Color="{Binding MyForegroundColor,Converter={StaticResource ColorToSolidColorBrush_ValueConverter}}"/>
            <Image x:Key="yuserimg" Height="50" Width="50" Source="{Binding userimg}"/>
        </DataGrid.Resources>
        <DataGrid.ColumnHeaderStyle>
            <Style TargetType="{x:Type DataGridColumnHeader}">
                <Setter Property="HorizontalContentAlignment" Value="Left" />
                <Setter Property="FontWeight" Value="bold"/>
                <Setter Property="Margin" Value="0"/>
                <Setter Property="Padding" Value="1" />
                <Setter Property="Background" Value="Transparent" />
                <Setter Property="BorderThickness" Value="1"/>
            </Style>
        </DataGrid.ColumnHeaderStyle>
        <DataGrid.RowStyle>
            <Style TargetType="DataGridRow" >
                <Setter Property="ToolTip" Value="{Binding yuserimg}"/>
                <Style.Triggers>
                    <DataTrigger Binding="{Binding Path=CNIsOnline,UpdateSourceTrigger=PropertyChanged}" Value="False">
                        <Setter Property="Background" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}},Path=DataContext.OfflineColor,UpdateSourceTrigger=PropertyChanged}"></Setter>
                    </DataTrigger>
                    <DataTrigger Binding="{Binding Path=CNIsOnline,UpdateSourceTrigger=PropertyChanged}" Value="True">
                        <Setter Property="Background" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}},Path=DataContext.OnlineColor,UpdateSourceTrigger=PropertyChanged}"></Setter>
                    </DataTrigger>
                    <DataTrigger Binding="{Binding Path=CNIsOnline,UpdateSourceTrigger=PropertyChanged}" Value="{x:Null}">
                        <Setter Property="Background" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}},Path=DataContext.UnknownColor,UpdateSourceTrigger=PropertyChanged}"></Setter>
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </DataGrid.RowStyle>
    </DataGrid>

但是，当我将鼠标悬停在一行上时，我现在根本看不到任何工具提示弹出。

更新 2

我更新了对动态资源的绑定：

            <DataGrid.Resources>
            <Style TargetType="ScrollBar">
                <Setter Property="Opacity" Value=".3" />
            </Style>
            <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="{Binding MyAccentColor,Converter={StaticResource ColorToSolidColorBrush_ValueConverter}}"/>
            <SolidColorBrush x:Key="{x:Static SystemColors.HighlightTextBrushKey}" Color="{Binding MyForegroundColor,Converter={StaticResource ColorToSolidColorBrush_ValueConverter}}"/>
            <SolidColorBrush x:Key="{x:Static SystemColors.InactiveSelectionHighlightBrushKey}"  Color="{Binding MyAccentColor,Converter={StaticResource ColorToSolidColorBrush_ValueConverter}}"/>
            <SolidColorBrush x:Key="{x:Static SystemColors.InactiveSelectionHighlightTextBrushKey}" Color="{Binding MyForegroundColor,Converter={StaticResource ColorToSolidColorBrush_ValueConverter}}"/>
            <Image x:Key="yuserimg" Height="50" Width="50" Source="{Binding userimg}"/>
        </DataGrid.Resources>


            <DataGrid.RowStyle>
            <Style TargetType="DataGridRow" >
                <Setter Property="ToolTip" Value="{DynamicResource yuserimg}"/>
                <Style.Triggers>
                    <DataTrigger Binding="{Binding Path=CNIsOnline,UpdateSourceTrigger=PropertyChanged}" Value="False">
                        <Setter Property="Background" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}},Path=DataContext.OfflineColor,UpdateSourceTrigger=PropertyChanged}"></Setter>
                    </DataTrigger>
                    <DataTrigger Binding="{Binding Path=CNIsOnline,UpdateSourceTrigger=PropertyChanged}" Value="True">
                        <Setter Property="Background" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}},Path=DataContext.OnlineColor,UpdateSourceTrigger=PropertyChanged}"></Setter>
                    </DataTrigger>
                    <DataTrigger Binding="{Binding Path=CNIsOnline,UpdateSourceTrigger=PropertyChanged}" Value="{x:Null}">
                        <Setter Property="Background" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}},Path=DataContext.UnknownColor,UpdateSourceTrigger=PropertyChanged}"></Setter>
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </DataGrid.RowStyle>

但是，我仍然遇到绑定错误，我只看到一个 50x50 的框作为工具提示。

以下是绑定错误：

System.Windows.Data Information: 41 : BindingExpression path error: 'userimg' property not found for 'object' because data item is null.  This could happen because the data provider has not produced any data yet. BindingExpression:Path=userimg; DataItem=null; target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource')
System.Windows.Data Information: 20 : BindingExpression cannot retrieve value due to missing information. BindingExpression:Path=userimg; DataItem=null; target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource')
System.Windows.Data Information: 21 : BindingExpression cannot retrieve value from null data item. This could happen when binding is detached or when binding to a Nullable type that has no value. BindingExpression:Path=userimg; DataItem=null; target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource')
System.Windows.Data Information: 10 : Cannot retrieve value using the binding and no valid fallback value exists; using default instead. BindingExpression:Path=userimg; DataItem=null; target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource')

Answer 1

您不能编辑您发布的代码。 我不得不删除原始帖子并创建另一个只是为了将绑定更改为动态资源。