如何动态更改ListBox项的颜色（使用绑定到它的类对象列表）？ C＃UWP

我使用两个ListBox元素 . 一个是父（BucketListBox），它决定了应该在子节目中显示的内容 . Child（ObjectListBox）处于多选模式 . 一旦我选择了子元素中的特定元素，我转移到另一个父元素，子元素ListBox将更新为新的选择 .

当用户切换回先前浏览过的父母时，他应该能够看到他当时选择的孩子中的旧选择 . 我正在维护用户在孩子中选择的项目列表 . 我想使用此列表来更改他之前选择的元素的背景颜色 .

截至目前，这些元素仍处于选中状态，但未在UI中显示 .

这是我父母的XAML代码：

<ListBox Grid.Row="1" x:Name="BucketListBox" HorizontalContentAlignment="Stretch" SelectionChanged="BucketListBox_SelectionChanged">
<ListBox.ItemTemplate>
    <DataTemplate>
        <Grid Margin="10,10,10,10">
            <Grid.RowDefinitions>
                <RowDefinition Height="2*"/>
                <RowDefinition Height="1*"/>
            </Grid.RowDefinitions>
            <RelativePanel Grid.Row="0">
                <TextBlock x:Name="BucketNameLabel" x:Uid="NameLabel"/>
                <TextBlock Grid.Row="0" x:Name="BucketNameTextBlock" RelativePanel.AlignBottomWith="BucketNameLabel" RelativePanel.RightOf="BucketNameLabel" Text="{Binding BucketName}" Margin="10,10,10,10"/>
            </RelativePanel>
            <RelativePanel Grid.Row="1">
                <TextBlock x:Name="BucketCreationDateLabel" FontSize="12" x:Uid="CreationDateLabel" HorizontalAlignment="Right"/>
                <TextBlock x:Name="BucketCreationDateTextBlock" FontSize="12" RelativePanel.RightOf="BucketCreationDateLabel" RelativePanel.AlignBottomWith="BucketCreationDateLabel" Text="{Binding BucketCreationDate}" Margin="10,10,10,10" HorizontalAlignment="Right" />
            </RelativePanel>
        </Grid>
    </DataTemplate>
</ListBox.ItemTemplate>

子ListBox的代码：

<ListBox Grid.Row="1" Grid.Column="1" x:Name="ObjectListBox" HorizontalContentAlignment="Stretch" SelectionMode="Multiple">

        <ListBox.ItemTemplate >
            <DataTemplate >
                <Grid Margin="10,10,10,10">
                    <Grid.RowDefinitions>
                        <RowDefinition Height="2*"/>
                        <RowDefinition Height="1*"/>
                        <RowDefinition Height="1*"/>
                    </Grid.RowDefinitions>
                    <RelativePanel Grid.Row="0">
                        <TextBlock x:Name="NameLabel" x:Uid="NameLabel" Margin="10,10,10,10" />
                        <TextBlock x:Name="ObjectNameTextBlock" Text="{Binding ObjectName}" RelativePanel.RightOf="NameLabel" RelativePanel.AlignBottomWith="NameLabel" Margin="10,10,10,10" />
                    </RelativePanel>
                    <RelativePanel Grid.Row="1">
                        <TextBlock x:Name="SizeLabel" FontSize="12" x:Uid="SizeLabel"/>
                        <TextBlock x:Name="ObjectSize" FontSize="12" Margin="10,10,10,10" Text="{Binding Path=ObjectSize}" RelativePanel.RightOf="SizeLabel" RelativePanel.AlignBottomWith="SizeLabel"/>
                    </RelativePanel>
                    <RelativePanel Grid.Row="2">
                        <TextBlock x:Name="ObjectModificationDateLabel" FontSize="12" x:Uid="ModificationDateLabel" Margin="10,10,10,10" HorizontalAlignment="Right"/>
                        <TextBlock x:Name="ObjectModificationDateTextBlock" FontSize="12" Text="{Binding ObjectLastModificationDate}" Margin="10,10,10,10" RelativePanel.RightOf="ObjectModificationDateLabel" RelativePanel.AlignBottomWith="ObjectModificationDateLabel" HorizontalAlignment="Right"/>
                    </RelativePanel>

                </Grid>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>

这里是更新ListBoxItem的代码:(每当用户点击父ListBox中的新项时调用）

private void UpdateListBoxWithSelectedItems()
    {
        List<S3ObjectInfoHolder> currentList = (List<S3ObjectInfoHolder>)ObjectListBox.ItemsSource; //Getting the total elements being displayed in the current child list box
        foreach (S3ObjectInfoHolder entry in listOfObjectsToTransfer) //listOfObjectsToTransfer is the list of all the entries from all the parents selected so far. So the intersection of currentList with this list gives the ones that are to be colored on UI so as the user knows the items are still selected
        {
            for (int i = 0; i < currentList.Count(); i++)
            {
                if (currentList[i].ObjectName.Equals(entry.ObjectName))
                {
                    ObjectListBox.SelectedItems.Add(entry);
                    Debug.WriteLine("Selected Item:" + entry.ObjectName);
                }
            }
        }
        List<object> selectedItem = ObjectListBox.SelectedItems.ToList();
        foreach (object item in selectedItem)
        {
            ListBoxItem selectedListBoxItem = ObjectListBox.ItemContainerGenerator.ContainerFromItem((S3ObjectInfoHolder)item) as ListBoxItem;
            if(selectedListBoxItem!=null) selectedListBoxItem.Background = new SolidColorBrush(Colors.Turquoise);
        }
    }

selectedListBoxItem!=null 失败，并跳过该行 . 最后，这是绑定类的代码：

class S3ObjectInfoHolder
{
    private string key;
    private string bucketName;
    private long size;
    private string isObjectAFolder;
    private string objectLastModificationDate;

    public S3ObjectInfoHolder(string key, string bucketName)
    {
        this.key = key;
        this.bucketName = bucketName;
        isObjectAFolder = isObjectAFolderOrAFile(key);
    }

    private string isObjectAFolderOrAFile(string key)
    {
        if (key[key.Length - 1] == '/')
        {
            return "is a Folder";
        }
        else
        {
            return "is a File";
        }
    }

    public string ObjectName
    {
        get
        {
            return key;
        }

        set
        {
            key = value;
        }
    }

    public long ObjectSize
    {
        get
        {
            return size;
        }

        set
        {
            size = value;
        }
    }

    public string ObjectIsFolder
    {
        get
        {
            return isObjectAFolder;
        }

        set
        {
            isObjectAFolder = value;
        }
    }

    public string BucketName
    {
        get
        {
            return bucketName;
        }

        set
        {
            bucketName = value;
        }
    }

    public string ObjectLastModificationDate
    {
        get
        {
            return objectLastModificationDate;
        }

        set
        {
            objectLastModificationDate = value;
        }
    }

}