Question

有以下ListBox

<ListBox x: Name = "ListBoxQuestionAnswers" ItemsSource = "{x: Bind Question.Answers}" SelectionMode = "Single" SelectionChanged = "ListBoxQuestionAnswers_OnSelectionChanged">
    <ListBox.ItemTemplate>
        <DataTemplate>
            <TextBlock x: Name = "TextBlockInListBox" TextWrapping = "Wrap" Text = "{Binding}" />
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

Question.Answers - List<string>。有必要在ListBox单击处理程序中更改所选项的颜色。现在处理程序代码如下所示：

private void ListBoxQuestionAnswers_OnSelectionChanged (object sender, SelectionChangedEventArgs e)
{
    if (ListBoxQuestionAnswers.SelectedIndex == Question.CorrectAnswerIndex)
    {
        Application.Current.Resources ["SystemControlHighlightListAccentLowBrush"] = new SolidColorBrush (Colors.Green);
        Application.Current.Resources ["SystemControlHighlightListAccentMediumBrush"] = new SolidColorBrush (Colors.Green);
    }
    else
    {
        Application.Current.Resources ["SystemControlHighlightListAccentLowBrush"] = new SolidColorBrush (Colors.Red);
        Application.Current.Resources ["SystemControlHighlightListAccentMediumBrush"] = new SolidColorBrush (Colors.Red);
    }

}

此方法存在的问题是应用程序中的颜色会发生变化。 SelectedItem的颜色仅在此ListBox中发生了什么变化？

Answer 1

您正在修改Application.Current.Resources，这将影响所有列表视图。而是改变控件实例上的资源：

private void ListBoxQuestionAnswers_OnSelectionChanged (object sender, SelectionChangedEventArgs e)
{
    if (ListBoxQuestionAnswers.SelectedIndex == Question.CorrectAnswerIndex)
    {
        ListBoxQuestionAnswers.Resources ["SystemControlHighlightListAccentLowBrush"] = new SolidColorBrush (Colors.Green);
        ListBoxQuestionAnswers.Resources ["SystemControlHighlightListAccentMediumBrush"] = new SolidColorBrush (Colors.Green);
    }
    else
    {
        ListBoxQuestionAnswers.Resources ["SystemControlHighlightListAccentLowBrush"] = new SolidColorBrush (Colors.Red);
        ListBoxQuestionAnswers.Resources ["SystemControlHighlightListAccentMediumBrush"] = new SolidColorBrush (Colors.Red);
    }

}

每个FrameworkElement都可以拥有自己的资源，在走向父元素（如网页或应用）之前先查看这些资源，以寻找合适的资源。

如何更改SelectedItem的颜色（在ListBox中）？

1 个答案: