Silverlight实现可换行换列的CheckBoxList

在Silverlight中实现CheckBoxList一般都使用ListBox+CheckBox实现
但如何实现类似Asp.net控件CheckBoxList的RepeatColumns功能呢?
如下图所示:

主要用到了ListBox的ItemsPanel,其中放入了一个ControlsToolkit的WrapPanel
一些国外的论坛里都提到用ListBox的父类控件ItemsControl
其实大可不必,ListBox本身就拥有ItemsPanel,在派生时还加入了ScrollViewer,也就是自带滚动条
而ItemsControl是没有ScrollViewer的,需要用一个ScrollViewer包住,何必多此一举呢?

<UserControl
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:controlsToolkit="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Toolkit" 
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    x:Class="SilverlightSample.UcTest2"
    mc:Ignorable="d" >
    <Grid x:Name="LayoutRoot" Background="White" Height="272" Width="392">
        <Grid Height="150" Margin="20,22,20,100">
                <ListBox  x:Name="checkBoxList1">
                    <ListBox.ItemsPanel>
                        <ItemsPanelTemplate>
                            <!--WrapPanel的Height除以CheckBox的Height决定每列的行数-->
                            <!--暂未找到可以设置WrapPanel折行数量的属性-->
                            <!--Orientation设置纵向或横向排列,横向的话需要用Width设置-->
                            <controlsToolkit:WrapPanel Orientation="Vertical" Height="100" />
                        </ItemsPanelTemplate>
                    </ListBox.ItemsPanel>
                    <ListBox.ItemTemplate>
                        <DataTemplate>
                            <!--这里的Selected属性设置双向绑定是为了筛选选中的项目-->
                            <CheckBox IsChecked="{Binding Selected, Mode=TwoWay}" Height="16" >
                                <TextBlock Text="{Binding Name}" FontSize="13"  />
                            </CheckBox>
                        </DataTemplate>
                    </ListBox.ItemTemplate>
                </ListBox>
        </Grid>
        <Button Margin="179,199,94,41" Content="获取选中" FontSize="13"  Click="Button_Click"/>
    </Grid>
</UserControl>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

using SilverlightSample.ServiceReference;

namespace SilverlightSample
{
    public partial class UcTest2 : UserControl
    {
        public UcTest2()
        {
            InitializeComponent();

            WebServiceSoapClient sc = new WebServiceSoapClient();

            sc.getCategoryListCompleted += (s, e) =>
            {
                if (e.Error == null)
                {
                    checkBoxList1.ItemsSource = e.Result;
                }
            };

            sc.getCategoryListAsync();
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            //获取选中的项目
            IEnumerable<Category> list = (IEnumerable<Category>)checkBoxList1.ItemsSource;
            IEnumerable<Category> selectedList=list.Where(a=>a.Selected==true);
        }
    }
}

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.Services;
/// <summary>
///WebService 的摘要说明
/// </summary>
[WebService(Namespace = "http://www.shanghaimart.com/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
public class WebService : System.Web.Services.WebService
{
    public WebService()
    {

        //如果使用设计的组件，请取消注释以下行 
        //InitializeComponent(); 
    }
    [WebMethod]
    public List<Category> getCategoryList()
    {
        List<Category> list = new List<Category>();
        list.Add(new Category(1, "搭建管理费", true));
        list.Add(new Category(2, "电费", false));
        list.Add(new Category(3, "广告阵地费", true));
        list.Add(new Category(4, "加班费", false));
        list.Add(new Category(5, "物品损坏赔偿", true));
        list.Add(new Category(6, "空调费", false));
        list.Add(new Category(7, "展会折扣", true));
        list.Add(new Category(8, "租用物品", false));
        list.Add(new Category(9, "展厅增租", true));
        list.Add(new Category(10, "开幕式服务", false));
        list.Add(new Category(11, "租金", true));
        list.Add(new Category(12, "押金", false));
        list.Add(new Category(13, "服务费", true));
        list.Add(new Category(14, "收款", false));
        list.Add(new Category(15, "保证金", true));
        list.Add(new Category(16, "定金", false));
        list.Add(new Category(17, "税费", false));
        return list;
    }
}
[Serializable]
public class Category
{
    public Category()
    { }
    public Category(int id, string name, bool selected)
    {
        ID = id;
        Name = name;
        Selected = selected;
    }
    public int ID;
    public string Name;
    public bool Selected;
}