无法在CollectionViewGroup中找到ToggleButton

本文关键字：ToggleButton CollectionViewGroup | 更新日期: 2023-09-27 18:07:17

我试图找到一个ToggleButton关联在我的CollectionViewGroup，我的xaml结构如下:

 <UserControl.Resources>
    <CollectionViewSource Source="{Binding Matches}" x:Key="GroupedItems">
        <CollectionViewSource.GroupDescriptions>
            <PropertyGroupDescription PropertyName="MatchNation" />
            <PropertyGroupDescription PropertyName="MatchLeague" />
        </CollectionViewSource.GroupDescriptions>
</UserControl.Resources>

你怎么能看到我有一个CollectionViewGroup过滤ObservableCollection结合的Matches为Nation和League。

为此，我声明了一个ListView，其中有两个GroupStyle，一个用于Country和另一个用于League，在这段代码中，我只添加了第二个GroupStyle(包含ToggleButton):

<ListView ItemsSource="{Binding Source={StaticResource GroupedItems}}">
    <!-- this is the second group style -->
    <ListView.GroupStyle>
         <GroupStyle>
            <GroupStyle.ContainerStyle>
                <Style TargetType="{x:Type GroupItem}" >
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate>
                                <Expander IsExpanded="True" Background="#4F4F4F">
                                    <Expander.Header>
                                        <DockPanel Height="16.5">
                                            <TextBlock Text="{Binding Name}" FontWeight="Bold" Foreground="White" FontSize="11.5" VerticalAlignment="Bottom" />
                                            <ToggleButton Checked="{Binding IsFavourite}" HorizontalAlignment="Right"/>
                                        </DockPanel>
                                    </Expander.Header>
                                    <ItemsPresenter />
                                </Expander>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </GroupStyle.ContainerStyle>
        </GroupStyle>
    </ListView.GroupStyle>
</ListView>

那么，你可以看到在第二组样式(Nation -> League)我有一个ToggleButton。

现在，GroupStyle将根据ObservableCollection中可用的项进行重复，例如:

|England
    |Premier League
     1. item  
     2. item 
     3. item 
|Afghanistan
     |Afghan Premier League
     1. item 
     2. item

这就是组织，现在想象一下，对于England的Premier League和Afghanistan的Afghan Premier League，我在右边插入了一个ToggleButton，我需要在列表中获得每个Group的所有ToggleButtons。我试过了:

var playingListSource = (ListCollectionView).Playing.Items.SourceCollection;
foreach (var gp in playingListSource.Groups)
{
       var rootGroup = (CollectionViewGroup)gp; //Convert the nested group
       var parentGroup = rootGroup.Items;
}

基本上，我提取了列表的Group，并试图找到巢组上的ToggleButton，但我找不到它。有人能帮帮我吗?

无法在CollectionViewGroup中找到ToggleButton

首先，如果我们命名ToggleButton以便稍后可以使用ControlTemplate.FindName方法，事情将会容易得多。这里是ToggleButton:

<ToggleButton x:Name="PART_ToggleButton"
              Checked="{Binding IsFavourite}"
              HorizontalAlignment="Right" />

我们现在需要的是得到模板化的容器(一个GroupItem控件)。我们可以使用ListView.ItemContainerGenerator.ContainerFromItem方法。

知道这里有一段代码应该检索有问题的ToggleButton:

//we assume listView is a reference to the ListView
var playingListSource = (ListCollectionView)listView.ItemsSource;
//first we iterate over the top-level groups
foreach (CollectionViewGroup nationGroup in playingListSource.Groups)
{
    //second-level groups are items of their parents
    foreach (CollectionViewGroup leagueGroup in nationGroup.Items)
    {
        //first we retrieve the GroupItem control associated with current second-level group
        var container = listView.ItemContainerGenerator.ContainerFromItem(leagueGroup) as GroupItem;
        //then we find the named ToggleButton inside the template
        var toggleButton = container.Template.FindName("PART_ToggleButton", container) as ToggleButton;
        //at this point we have a reference to the ToggleButton
    }
}
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