AutoCompleteBox组件的自定义 FilterMode和自定义ItemFilter研究

需求分析：现在有表 City( name ,shortName)  eg： city:广州 ，GZ ；上海，SH

在AutoCompleteBox 中输入“G”、GZ或“广”、“ 广州”都自动弹出“ 广州”.

实现

1.

<UserControl xmlns:input="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Input"  x:Class="SilverlightAutoComboxNameOrShortName.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480">
  <Grid x:Name="LayoutRoot">      
        <input:AutoCompleteBox FilterMode="Custom" x:Name="acb"  Width="150" Height="30"></input:AutoCompleteBox>
    </Grid>
</UserControl>

2.city类 ，并重写Tostring 方法

 public class City
    {
        public string Name { get; set; }
        public string ShortName { get; set; }      

        public override string ToString() { return Name; }

    }

3.mainpage

  public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();
            this.Loaded += new RoutedEventHandler(MainPage_Loaded);
        }

        void MainPage_Loaded(object sender, RoutedEventArgs e)
        {                       
            //为AutoCompleteBox提供数据源           
            acb.ItemsSource = GetCities();
            
            //过滤模式为自定义        

            //自定义过滤条件
            acb.ItemFilter = (search, item) =>
            {
                City city = item as City;
                if (city != null)
                {
                    string filter = search.ToLower();
                    //包含filter返回true
                    return city.Name.Contains(filter) ||
                        city.ShortName.ToLower().Contains(filter);
                }
                return false;
             }; 
        }

        List<City> GetCities()
        {
            List<City> cs = new List<City>();
            cs.Add(new City { Name = "广州", ShortName = "GZ" });
            cs.Add(new City { Name = "南京", ShortName = "NJ" });
            cs.Add(new City { Name = "上海", ShortName = "SH" });
            cs.Add(new City { Name = "北京", ShortName = "BJ" });
            cs.Add(new City { Name = "扬州", ShortName = "YZ" });
            cs.Add(new City { Name = "杭州", ShortName = "HZ" });
            return cs;
        }
       
    }

4.图示