将焦点设置在 ListBox 项上会中断键盘导航 [英] Setting focus on a ListBox item breaks keyboard navigation

问题描述

以编程方式选择 ListBox 项目后，需要按向下向上键 两次 移动选择.有什么建议吗?

After selecting ListBox item programmatically it is needed to press downup key two times to move the selection. Any suggestions?

查看:

<ListBox Name="lbActions" Canvas.Left="10" Canvas.Top="10"
               Width="260" Height="180">
        <ListBoxItem Name="Open" IsSelected="true" Content="Open"></ListBoxItem>
        <ListBoxItem Name="Enter" Content="Enter"></ListBoxItem>
        <ListBoxItem Name="Print" Content="Print"></ListBoxItem>
</ListBox>

代码:

public View()
{
   lbActions.Focus();
   lbActions.SelectedIndex = 0; //not helps
   ((ListBoxItem) lbActions.SelectedItem).Focus(); //not helps either
}

推荐答案

不要将焦点设置到 ListBox... 将焦点设置到选定的 ListBoxItem.这将解决需要敲击两次键盘"的问题:

Don't set the focus to the ListBox... set the focus to the selected ListBoxItem. This will solve the "two keyboard strokes required" problem:

if (lbActions.SelectedItem != null)
    ((ListBoxItem)lbActions.SelectedItem).Focus();
else
    lbActions.Focus();

如果您的 ListBox 包含的不是 ListBoxItems，您可以使用 lbActions.ItemContainerGenerator.ContainerFromIndex(lbActions.SelectedIndex) 来获取自动生成的 ListBoxItem.

If your ListBox contains something else than ListBoxItems, you can use lbActions.ItemContainerGenerator.ContainerFromIndex(lbActions.SelectedIndex) to get the automatically generated ListBoxItem.

如果您希望在 窗口初始化 期间发生这种情况，您需要将代码放入 Loaded 事件中，而不是放入构造函数中.示例 (XAML):

If you want this to happen during window initialization, you need to put the code in the Loaded event rather than into the constructor. Example (XAML):

<Window ... Loaded="Window_Loaded">
    ...
</Window>

代码(基于您问题中的示例):

Code (based on the example in your question):

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        lbActions.Focus();
        lbActions.SelectedIndex = 0;
        ((ListBoxItem)lbActions.SelectedItem).Focus();
    }

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