将焦点设置为模板中的特定元素，并选择该项

Question

拥有带模板选择器的ListView

当选择此ListBoxItem（点击或箭头）时，我需要的是名为tbStringSVfieldValue的TextBox获得焦点？

<DataTemplate x:Key="fieldTemplateStringSV">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="4*" />
        </Grid.ColumnDefinitions>
        <TextBlock Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="4" Text="Enter key to save. Tab to get the first match from existing values.  Value is only committed on Enter key."  VerticalAlignment="Center" Style="{StaticResource Italic}"/>
        <ScrollViewer Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="3" VerticalContentAlignment="Stretch" 
            HorizontalScrollBarVisibility="Disabled" VerticalScrollBarVisibility="Auto">
            <TextBox x:Name="tbStringSVfieldValue" BorderBrush="SteelBlue" BorderThickness="2" TextWrapping="Wrap" 
                Text="{Binding Path=FieldValue, Mode=TwoWay, ValidatesOnExceptions=True, NotifyOnValidationError=True, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource stringTabConverter}}"
                Validation.Error="Validataion_Error" AcceptsReturn="True" AcceptsTab="True"
                PreviewKeyDown="tbStringSVfieldValue_PreviewKeyDown"/>
            <!--, Converter={StaticResource stringTabConverter}-->
        </ScrollViewer>
        <TextBlock Grid.Row="2" Grid.Column="0" Grid.ColumnSpan="4" Text="Existing values. Click to populate the value above."  VerticalAlignment="Center" Style="{StaticResource Italic}"/>
        <ListBox Grid.Row="3" Grid.Column="0" Grid.ColumnSpan="4" Height="150" Margin="5,2,0,0" x:Name="lbSVtextPast" ScrollViewer.VerticalScrollBarVisibility="Auto" ScrollViewer.IsDeferredScrollingEnabled="True"
                FontStyle="Normal"
                ItemsSource="{Binding Path=PastEntries}" SelectedItem="{Binding Path=SelectedPastEntry}"
                SelectionChanged="lbSVtextPastSelectionChanged"/>
    </Grid>
</DataTemplate>

上面我试过

<Grid FocusManager.FocusedElement="{Binding ElementName=svTBsv}">
    <ScrollViewer x:Name="svTBsv" Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="3" VerticalContentAlignment="Stretch" 
        HorizontalScrollBarVisibility="Disabled" VerticalScrollBarVisibility="Auto"
        FocusManager.FocusedElement="{Binding ElementName=tbStringSVfieldValue}">
        <TextBox x:Name="tbStringSVfieldValue" BorderBrush="SteelBlue" 

下面注意不起作用 this.tbStringSVfieldValueStringSV为空
它只存在于模板中 需要以某种方式访问​​正确的模板
请注意ListBox中将有多个DataTemplate x：Key =“fieldTemplateStringSV”

private void lbCurDocFields_SelectionChanged(object sender, SelectionChangedEventArgs e)
{   
    MessageBox.Show("lbCurDocFields_SelectionChanged " + sender.GetType().ToString());
    if (sender is ListBox)
    {
        ListBox lb = (ListBox)sender;
        //lb.Template.VisualTree;
        MessageBox.Show(lb.Template.ToString());
        if (lb.SelectedItem != null)
        {
            MessageBox.Show(lb.SelectedItem.GetType().ToString());
            if (lb.SelectedItem is GabeLib.DocFieldStringSV)
            {
                if (this.tbStringSVfieldValueStringSV != null)
                    this.tbStringSVfieldValueStringSV.Focus();
            }