Xamarin 列表视图分组 [英] Xamarin Listview grouping

问题描述

我正在处理 xamarin.froms 中的列表视图.我可以轻松地为每条记录使用一个列表项填充列表视图:

<预><代码>[{猫":1，名称":阿尔法"}，{猫":1，名称":测试版"}，{猫":1，名称":伽玛"}，{"cat":2, "name":"john"},{"cat":2, "name":"william"},{"cat":2, "name":"smith"},{"cat":2, "name":"steve"},{"cat":3, "name":"abc"},{猫":3，名称":xyz"}]

//来自这个json源的listview中的9个项目

但我想要的是根据某个键值对所有项目进行分组，在这里说 "cat" 并实现如下所示:

对此的任何建议或方法将不胜感激.

解决方案

将您的数据分组到集合中，并将这些集合添加到您的 ListView 中.集合需要是您自己的类，具有用于绑定组的属性.

这是一个演练:

在 ListView 上设置分组，包括将每个组绑定到的属性，在本例中为GroupKey"

 myListView.IsGroupingEnabled = true;myListView.GroupDisplayBinding = new Binding("GroupKey");//见下文

然后添加您的数据分组(例如列表列表).这通常意味着您需要创建自己的类来显示您的分组，例如:

 公共类分组:ObservableCollection{//注意:这是上面用于显示标题的 GroupDisplayBinding公共 K 组密钥 { 获取；私人订制；}公共分组(K 键，IEnumerable 项)ac{GroupKey = 密钥；foreach (var item in items)this.Items.Add(item);}}

最后，按组添加您的数据:

 var groups = new ObservableCollection>();//你可以只传入一组数据(其中GroupA"是一个可枚举集)groups.Add(new Grouping("GroupA", GroupA));//或者过滤一组数据groups.Add(new Grouping("GroupB",MyItems.Where(a => a.SomeFilter())));myListView.ItemSource = 组；

像以前一样将您的单元格绑定到 MyDataClass:

 var cell = new DataTemplate(typeof(TextCell));cell.SetBinding(TextCell.TextProperty, "SomePropertyFromMyDataClass");cell.SetBinding(TextCell.DetailProperty, "OtherPropertyFromMyDataClass");myListView.ItemTemplate = 单元格；

查看它以了解为什么使用模板 K 而不是 Grouping 类中的字符串、如何自定义标题外观等等:
http://motzcod.es/post/94643411707/enhancing-xamarinforms-带分组的列表视图

(归功于@pnavk 回答中的链接)

I am dealing with a listview in xamarin.froms. I can easily populate the listview with a listitem for each record:

[
    {"cat":1, "name":"alpha"},
    {"cat":1, "name":"beta"},
    {"cat":1, "name":"gamma"},
    {"cat":2, "name":"john"},
    {"cat":2, "name":"william"},
    {"cat":2, "name":"smith"},
    {"cat":2, "name":"steve"},
    {"cat":3, "name":"abc"},
    {"cat":3, "name":"xyz"}
]

//9 Items in listview from this json source

But what I want is to group all the items on some key value, say "cat" here and achieve something like this:

Any suggestion or approach toward this would be appreciated.

解决方案

Group your data into collections and add those collections into your ListView. The collections need to be your own class with a property for binding the group with.

Here's a walkthrough:

Set up grouping on your ListView including a property to bind each group to, in this case "GroupKey"

    myListView.IsGroupingEnabled = true;
    myListView.GroupDisplayBinding = new Binding("GroupKey"); // See below

And then add your data in groups (e.g. lists of lists). This often means you need to create your own class to show your groupings, such as:

    public class Grouping<K, T> : ObservableCollection<T>
    {
        // NB: This is the GroupDisplayBinding above for displaying the header
        public K GroupKey { get; private set; } 

        public Grouping(K key, IEnumerable<T> items)ac
        {
            GroupKey = key;
            foreach (var item in items)
                this.Items.Add(item);
        }
    }

And finally, add your data in groups:

    var groups = new ObservableCollection<Grouping<string, MyDataClass>>();

    // You can just pass a set of data in (where "GroupA" is an enumerable set)
    groups.Add(new Grouping<string, MyDataClass>("GroupA", GroupA)); 

    // Or filter down a set of data
    groups.Add(new Grouping<string, MyDataClass>("GroupB", 
        MyItems.Where(a => a.SomeFilter())));

    myListView.ItemSource = groups;

Bind your cell to the MyDataClass as you would have before:

    var cell = new DataTemplate(typeof(TextCell));
    cell.SetBinding(TextCell.TextProperty, "SomePropertyFromMyDataClass");
    cell.SetBinding(TextCell.DetailProperty, "OtherPropertyFromMyDataClass");
    myListView.ItemTemplate = cell;

Check it out for explanation on why to use template K instead of a string in the Grouping class, how to customise the header look, and much more:
http://motzcod.es/post/94643411707/enhancing-xamarinforms-listview-with-grouping

(Credit to the link in @pnavk's answer)

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