Windows Phone 8.1 列表控件（2）：分组数据

说到 List 控件，Windows Phone 8.1 上推荐使用的是 ListView 和 GridView。

而这两个控件实在太多东西可讲了，于是分成三篇来讲：

（1）基本

（2）分组数据

（3）多数据呈现

ListView 和 GridView 的最大差别就是：ListView 是一条条依序排列的，而 GridView 则是一块块依序排列的，因此 ListView 中的一项就会占据整整一行或者一列，而 GridView 的一项只会占据它应有的大小，一行或一列中可以放置多项。

而两者在其它方面上基本一致，因此下文只对 ListView 进行介绍，GridView 其实也一样的。

 

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分组数据（GroupingData）

分组数据也就是将数据按首字母或自定义属性进行分组，然后用户就能通过点击首字母或自定义属性达到快速定位的目的：

 

构建过程：

（1）准备已分好组的数据

数据的分组可分为两类，一是根据项的首字母或拼音分组，二是根据项的自身属性分组。

1）首字母或拼音分组

public static List<AlphaKeyGroup<SampleItem>> GetAlphaGroupSampleItems()
{
    ObservableCollection<SampleItem> data = new ObservableCollection<SampleItem>();
    data.Add(new SampleItem() { Title = "k1", Content = "k1", Image = "ms-appx:/Images/k1.png", Group = "Kill La Kill" });
    data.Add(new SampleItem() { Title = "w2", Content = "w2", Image = "ms-appx:/Images/w2.png", Group = "Wu Yu" });
    data.Add(new SampleItem() { Title = "k3", Content = "k3", Image = "ms-appx:/Images/k3.png", Group = "Kill La Kill" });
    data.Add(new SampleItem() { Title = "t4", Content = "t4", Image = "ms-appx:/Images/t4.png", Group = "Tiger" });
    data.Add(new SampleItem() { Title = "t5", Content = "t5", Image = "ms-appx:/Images/t5.png", Group = "Tiger" });
    data.Add(new SampleItem() { Title = "x6", Content = "x6", Image = "ms-appx:/Images/x6.png", Group = "Xi De Ni Ya" });
    data.Add(new SampleItem() { Title = "x7", Content = "x7", Image = "ms-appx:/Images/x7.png", Group = "Xi De Ni Ya" });
    data.Add(new SampleItem() { Title = "x8", Content = "x8", Image = "ms-appx:/Images/x8.png", Group = "Xi De Ni Ya" });
    data.Add(new SampleItem() { Title = "x9", Content = "x9", Image = "ms-appx:/Images/x9.png", Group = "Xi De Ni Ya" });
    data.Add(new SampleItem() { Title = "x10", Content = "x10", Image = "ms-appx:/Images/x10.png", Group = "Xi De Ni Ya" });
    data.Add(new SampleItem() { Title = "x11", Content = "x11", Image = "ms-appx:/Images/x11.png", Group = "Xi De Ni Ya" });


    List<AlphaKeyGroup<SampleItem>> groupData = AlphaKeyGroup<SampleItem>.CreateGroups(
                                                                                data,
                                                                                (SampleItem s) => { return s.Title; },
                                                                                true);
    return groupData;
}

AlphaKeyGroup 类为自己写的分组类：

public class AlphaKeyGroup<T>
{
    const string GlobeGroupKey = "\uD83C\uDF10";

    public string Key { get; private set; }

    public List<T> InternalList { get; private set; }

    public AlphaKeyGroup(string key)
    {
        Key = key;
        InternalList = new List<T>();
    }

    private static List<AlphaKeyGroup<T>> CreateDefaultGroups(CharacterGroupings slg)
    {
        List<AlphaKeyGroup<T>> list = new List<AlphaKeyGroup<T>>();

        foreach( CharacterGrouping cg in slg )
        {
            if( cg.Label == "" )
                continue;
            if( cg.Label == "..." )
            {
                list.Add(new AlphaKeyGroup<T>(GlobeGroupKey));
            }
            else
            {
                list.Add(new AlphaKeyGroup<T>(cg.Label));
            }
        }

        return list;
    }

    public static List<AlphaKeyGroup<T>> CreateGroups(IEnumerable<T> items, Func<T, string> keySelector, bool sort)
    {
        CharacterGroupings slg = new CharacterGroupings();
        List<AlphaKeyGroup<T>> list = CreateDefaultGroups(slg);

        foreach( T item in items )
        {
            int index = 0;
            {
                string label = slg.Lookup(keySelector(item));
                index = list.FindIndex(alphakeygroup => (alphakeygroup.Key.Equals(label, StringComparison.CurrentCulture)));
            }

            if( index >= 0 && index < list.Count )
            {
                list[index].InternalList.Add(item);
            }
        }

        if( sort )
        {
            foreach( AlphaKeyGroup<T> group in list )
            {
                group.InternalList.Sort((c0, c1) => { return keySelector(c0).CompareTo(keySelector(c0)); });
            }
        }

        return list;
    }
}

AlphaKeyGroup