重新想象 Windows 8 Store Apps (53)

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重新想象 Windows 8 Store Apps (53) - 绑定: 与 ObservableCollection CollectionViewSource VirtualizedFilesVector VirtualizedItemsVector 绑定　　
作者：webabcd

介绍
重新想象 Windows 8 Store Apps 之 绑定

• 与 ObservableCollection 绑定
  
• 与 CollectionViewSource 绑定
  
• 与 VirtualizedFilesVector 绑定
  
• 对 VirtualizedItemsVector 绑定
  

　　
示例
1、演示如何绑定 ObservableCollection 类型的数据
Binding/BindingObservableCollection.xaml






















　　Binding/BindingObservableCollection.xaml.cs



/*
* 演示如何绑定 ObservableCollection 类型的数据
*
* ObservableCollection - 在数据集合进行添加项、删除项、更新项、移动项等操作时提供通知
*     CollectionChanged - 当发生添加项、删除项、更新项、移动项等操作时所触发的事件（事件参数：NotifyCollectionChangedEventArgs）
*/
using System;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.Linq;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using XamlDemo.Model;
namespace XamlDemo.Binding
{
public sealed partial class BindingObservableCollection : Page
{
private ObservableCollection _employees;
public BindingObservableCollection()
{
this.InitializeComponent();
this.Loaded += BindingObservableCollection_Loaded;
}
void BindingObservableCollection_Loaded(object sender, RoutedEventArgs e)
{
_employees = new ObservableCollection(TestData.GetEmployees());
_employees.CollectionChanged += _employees_CollectionChanged;
listView.ItemsSource = _employees;
}
void _employees_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
/*
* e.Action - 引发此事件的操作类型（NotifyCollectionChangedAction 枚举）
*     Add, Remove, Replace, Move, Reset
* e.OldItems - Remove, Replace, Move 操作时影响的数据列表
* e.OldStartingIndex - Remove, Replace, Move 操作发生处的索引
* e.NewItems - 更改中所涉及的新的数据列表
* e.NewStartingIndex - 更改中所涉及的新的数据列表的发生处的索引
*/
}
private void btnDelete_Click_1(object sender, RoutedEventArgs e)
{
_employees.RemoveAt(0);
}
private void btnUpdate_Click_1(object sender, RoutedEventArgs e)
{
Random random = new Random();
// 此处的通知来自实现了 INotifyPropertyChanged 接口的 Employee
_employees.First().Name = random.Next(1000, 10000).ToString();
// 此处的通知来自 ObservableCollection
_employees[1] = new Employee() { Name = random.Next(1000, 10000).ToString() };
}
}
}
　　
2、演示如何绑定 CollectionViewSource 类型的数据，以实现数据的分组显示
Binding/BindingCollectionViewSource.xaml



























　　Binding/BindingCollectionViewSource.xaml.cs



/*
* 演示如何绑定 CollectionViewSource 类型的数据，以实现数据的分组显示
*
* CollectionViewSource - 对集合数据启用分组支持
*     Source - 数据源
*     View - 获取视图对象，返回一个实现了 ICollectionView 接口的对象
*     IsSourceGrouped - 数据源是否是一个被分组的数据
*     ItemsPath - 数据源中，子数据集合的属性名称
*     
* ICollectionView - 支持数据分组
*     CollectionGroups - 组数据集合
*     
*
* 注：关于数据分组的应用还可参见：XamlDemo/Index.xaml 和 XamlDemo/Index.xaml.cs
*/
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Data;
namespace XamlDemo.Binding
{
public sealed partial class BindingCollectionViewSource : Page
{
public BindingCollectionViewSource()
{
this.InitializeComponent();
this.Loaded += BindingCollectionViewSource_Loaded;
}
void BindingCollectionViewSource_Loaded(object sender, Windows.UI.Xaml.RoutedEventArgs e)
{
XElement root = XElement.Load("SiteMap.xml");
var items = LoadData(root);
// 构造数据源
CollectionViewSource groupData = new CollectionViewSource();
groupData.IsSourceGrouped = true;
groupData.Source = items;
groupData.ItemsPath = new PropertyPath("Items");
// 绑定 ICollectionView 类型的数据，以支持分组
listView.ItemsSource = groupData.View;
}
// 获取数据
private List LoadData(XElement root)
{
if (root == null)
return null;
var items = from n in root.Elements("node")
select new GroupModel
{
Title = (string)n.Attribute("title"),
Items = LoadData(n)
};
return items.ToList();
}
class GroupModel
{
public string Title { get; set; }
public List Items { get; set; }
}
}
}
　　
3、演示如何绑定 VirtualizedFilesVector
Binding/BindingVirtualizedFilesVector.xaml






















　　Binding/BindingVirtualizedFilesVector.xaml.cs



/*
* 演示如何绑定 VirtualizedFilesVector
*
* 本 Demo 演示了如何将图片库中的文件绑定到 GridView
*/
using Windows.Storage;
using Windows.Storage.BulkAccess;
using Windows.Storage.FileProperties;
using Windows.Storage.Search;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
namespace XamlDemo.Binding
{
public sealed partial class BindingVirtualizedFilesVector : Page
{
public BindingVirtualizedFilesVector()
{
this.InitializeComponent();
}
protected override void OnNavigatedTo(NavigationEventArgs e)
{
QueryOptions queryOptions = new QueryOptions();
queryOptions.FolderDepth = FolderDepth.Deep;
queryOptions.IndexerOption = IndexerOption.UseIndexerWhenAvailable;
queryOptions.SortOrder.Clear();
SortEntry sortEntry = new SortEntry();
sortEntry.PropertyName = "System.FileName";
sortEntry.AscendingOrder = true;
queryOptions.SortOrder.Add(sortEntry);
// 一个用于搜索图片库中的文件的查询
StorageFileQueryResult fileQuery = KnownFolders.PicturesLibrary.CreateFileQueryWithOptions(queryOptions);
// 创建一个 FileInformationFactory 对象
var fileInformationFactory = new FileInformationFactory(fileQuery, ThumbnailMode.PicturesView, 160, ThumbnailOptions.UseCurrentScale, true);
// 获取 VirtualizedFilesVector
itemsViewSource.Source = fileInformationFactory.GetVirtualizedFilesVector();
}
}
}
　　
4、演示如何绑定 VirtualizedItemsVector
Binding/BindingVirtualizedItemsVector.xaml





























　　Binding/BindingVirtualizedItemsVector.xaml.cs



/*
* 演示如何绑定 VirtualizedItemsVector
*
* 本 Demo 演示了如何将图片库中的顶级文件夹和顶级文件绑定到 GridView，同时演示了如何 runtime 时选择模板
*/
using Windows.Storage;
using Windows.Storage.BulkAccess;
using Windows.Storage.FileProperties;
using Windows.Storage.Search;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
namespace XamlDemo.Binding
{
public sealed partial class BindingVirtualizedItemsVector : Page
{
public BindingVirtualizedItemsVector()
{
this.InitializeComponent();
}
protected override void OnNavigatedTo(NavigationEventArgs e)
{
QueryOptions queryOptions = new QueryOptions();
queryOptions.FolderDepth = FolderDepth.Shallow;
queryOptions.IndexerOption = IndexerOption.UseIndexerWhenAvailable;
queryOptions.SortOrder.Clear();
SortEntry sortEntry = new SortEntry();
sortEntry.PropertyName = "System.IsFolder";
sortEntry.AscendingOrder = false;
queryOptions.SortOrder.Add(sortEntry);
SortEntry sortEntry2 = new SortEntry();
sortEntry2.PropertyName = "System.ItemName";
sortEntry2.AscendingOrder = true;
queryOptions.SortOrder.Add(sortEntry2);
// 一个用于搜索图片库中的顶级文件夹和顶级文件的查询
StorageItemQueryResult itemQuery = KnownFolders.PicturesLibrary.CreateItemQueryWithOptions(queryOptions);
// 创建一个 FileInformationFactory 对象
var fileInformationFactory = new FileInformationFactory(itemQuery, ThumbnailMode.PicturesView, 160, ThumbnailOptions.UseCurrentScale, true);
// 获取 VirtualizedItemsVector
itemsViewSource.Source = fileInformationFactory.GetVirtualizedItemsVector();
}
}
// 继承 DataTemplateSelector 以实现 runtime 时选择模板
public class FileFolderInformationTemplateSelector : DataTemplateSelector
{
// 显示文件时的模板
public DataTemplate FileInformationTemplate { get; set; }
// 显示文件夹时的模板
public DataTemplate FolderInformationTemplate { get; set; }
// 根据 item 的类型选择指定的模板
protected override DataTemplate SelectTemplateCore(object item, DependencyObject container)
{
var folder = item as FolderInformation;
if (folder == null)
return FileInformationTemplate;
else
return FolderInformationTemplate;
}
}
}
　　
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