如何同时使用 IsKeyboardFocusWithin 和 IsSelected? [英] How to use IsKeyboardFocusWithin and IsSelected together?

问题描述

我为我的 ListBoxItems 定义了一个样式，当 IsSelected 为 True 时，它​​带有一个触发器来设置背景颜色:

I have a style defined for my ListBoxItems with a trigger to set a background color when IsSelected is True:

    <Style x:Key="StepItemStyle" TargetType="{x:Type ListBoxItem}">
        <Setter Property="SnapsToDevicePixels" Value="true"/>
        <Setter Property="OverridesDefaultStyle" Value="true"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="ListBoxItem">
                    <Border Name="Border" Padding="0" SnapsToDevicePixels="true">
                        <ContentPresenter />
                    </Border>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsSelected" Value="True">
                            <Setter TargetName="Border" Property="Background" Value="#40a0f5ff"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

即使在 ListBox 和 ListBoxItem 失去焦点时，这种样式也会保持所选项目，在我的情况下这是绝对必须的.问题是我还希望在 TextBox 的其中一个子项获得焦点时选择 ListBoxItem.为了实现这一点，我添加了一个触发器，当 IsKeyboardFocusWithin 为 true 时将 IsSelected 设置为 true:

This style maintains the selected item even when the ListBox and ListBoxItem loses focus, which in my case is an absolute must. The problem is that I also want the ListBoxItem to be selected when one of its TextBox's child gets focused. To achieve this I add a trigger that sets IsSelected to true when IsKeyboardFocusWithin is true:

<Trigger Property="IsKeyboardFocusWithin" Value="True">
    <Setter Property="IsSelected" Value="True" />
</Trigger>

当我添加此触发器时，当焦点位于子 TextBox 上时选择了项目，但第一个行为消失了.现在，当我在 ListBox 外部单击时，该项目被取消选择.

When I add this trigger the Item is selected when the focus is on a child TextBox, but the first behaviour disappears. Now when I click outside the ListBox, the item is de-selected.

我怎样才能保持这两种行为?

How can I keep both behaviours?

推荐答案

当您的列表框失去焦点时，由于您的触发器，它会将选定项设置为空.您可以使用后面的一些代码选择焦点，当您失去焦点时不会取消选择.

When your listbox looses focus, it will set selected item to null because of your trigger. You can select on focus using some code behind that will not unselect when you loose focus.

XAML:

<Window x:Class="SelectedTest.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Height="300" Width="300">

    <StackPanel>
        <TextBox Text="Loose focus here" />
        <ListBox Name="_listBox" ItemsSource="{Binding Path=Items}">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal" GotFocus="OnChildGotFocus">
                        <TextBox Text="{Binding .}" Margin="10" />
                        <TextBox Text="{Binding .}" Margin="10" />
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
            <ListBox.ItemContainerStyle>
                <Style TargetType="{x:Type ListBoxItem}">
                    <Setter Property="SnapsToDevicePixels" Value="true"/>
                    <Setter Property="OverridesDefaultStyle" Value="true"/>
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate TargetType="ListBoxItem">
                                <Border Name="Border" SnapsToDevicePixels="true" Background="Transparent">
                                    <ContentPresenter />
                                </Border>
                                <ControlTemplate.Triggers>
                                    <Trigger Property="IsSelected" Value="True">
                                        <Setter TargetName="Border" Property="Background" Value="Red"/>
                                    </Trigger>                                   
                                </ControlTemplate.Triggers>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </ListBox.ItemContainerStyle>
        </ListBox>
    </StackPanel>
</Window>

后面的代码:

private void OnChildGotFocus(object sender, RoutedEventArgs e) 
{   
   _listBox.SelectedItem = (sender as StackPanel).DataContext; 
}

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