稳扎稳打Silverlight(50) - 4.0绑定之DependencyObject绑定, 索引器绑定, StringFormat, TargetNullValue和FallbackValue,

  [源码下载]

稳扎稳打Silverlight(50) - 4.0绑定之DependencyObject绑定,索引器绑定,StringFormat,TargetNullValue和FallbackValue,CollectionViewSource

作者： webabcd
介绍
Silverlight 4.0 绑定相关的增强：

• DependencyObject Binding - 新增了对 DependencyObject 绑定的支持 
• Indexer Binding - 新增了对索引器绑定的支持 
• StringFormat - 指定绑定数据的显示格式 
• TargetNullValue - 当绑定数据为 null 时所需要显示的值 
• FallbackValue - 当绑定失败（无法返回值）的时候所需要显示的值 
• CollectionViewSource - 实现了 ICollectionView 的类，可以通过它对数据排序、筛选和分组 

在线DEMO
http://www.cnblogs.com/webabcd/archive/2010/08/09/1795417.html
示例
1、演示如何绑定到 DependencyObject
DependencyObjectBinding.xaml

代码

< navigation:Page  x:Class ="Silverlight40.Binding.DependencyObjectBinding"  
           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"
           xmlns:navigation ="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"
           Title ="DependencyObjectBinding Page" >
     < Grid  x:Name ="LayoutRoot" >
         < StackPanel  HorizontalAlignment ="Left" >

             <!--  
                Silverlight 3.0 支持绑定到 FrameworkElement 
                    TextBox 继承自 FrameworkElement
             -->
             < TextBox  Text =" {Binding ElementName=slider, Path=Value} "   />

             <!--  
                Silverlight 4.0 中新增了对 DependencyObject 绑定的支持
                    RotateTransform 继承自 DependencyObject
             -->
             < Rectangle  Width ="100"  Height ="100"  RenderTransformOrigin ="0.5, 0.5"  Fill ="Red" >
                 < Rectangle.RenderTransform >
                     < RotateTransform  Angle =" {Binding ElementName=slider, Path=Value} "   />
                 </ Rectangle.RenderTransform >
             </ Rectangle  >

             < Slider  Name ="slider"  Height ="20"  Minimum ="0"  Maximum ="360"   />

         </ StackPanel >
     </ Grid >
</ navigation:Page >

2、演示如何绑定到索引器
IndexerBinding.xaml

代码

< navigation:Page  x:Class ="Silverlight40.Binding.IndexerBinding"  
           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"
           xmlns:navigation ="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"
           Title ="IndexerBinding Page" >
     < Grid  x:Name ="LayoutRoot" >

         <!--
            用于演示索引器的绑定
         -->
         < TextBlock  Name ="textBlock"  Text =" {Binding Path=[3] } "   />

     </ Grid >
</ navigation:Page >

IndexerBinding.xaml.cs

代码

/*
 * Silverlight 4.0 中新增了对索引器绑定的支持，索引的类型必须实现 IList
  */

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  System.Windows.Navigation;

namespace  Silverlight40.Binding
{
     public   partial   class  IndexerBinding : Page
    {
         public  IndexerBinding()
        {
            InitializeComponent();
        }

         protected   override   void  OnNavigatedTo(NavigationEventArgs e)
        {
            List < string >  list  =   new  List < string > ();
             for  ( int  i  =   0 ; i  <   10 ; i ++ )
            {
                list.Add( " 索引： "   +  i.ToString());
            }

            textBlock.DataContext  =  list;
        }
    }
}

3、演示在绑定时使用 StringFormat 来指定数据的显示格式
StringFormat.xaml

代码

< navigation:Page  x:Class ="Silverlight40.Binding.StringFormat"  
           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"
           xmlns:navigation ="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"
           Title ="StringFormat Page" >
     < Grid  x:Name ="LayoutRoot" >

         <!--
            StringFormat - 指定绑定数据的显示格式
         -->
         < TextBlock  Name ="textBlock"  Text =" {Binding StringFormat='yyyy-MM-dd HH:mm:ss'} "   />
        
     </ Grid >
</ navigation:Page >

StringFormat.xaml.cs

代码

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  System.Windows.Navigation;

namespace  Silverlight40.Binding
{
     public   partial   class  StringFormat : Page
    {
         public  StringFormat()
        {
            InitializeComponent();
        }

         protected   override   void  OnNavigatedTo(NavigationEventArgs e)
        {
            textBlock.DataContext  =  DateTime.Now;
        }
    }
}

4、演示 TargetNullValue 和 FallbackValue 的效果
TargetNullValueFallbackValue.xaml

代码

< navigation:Page  x:Class ="Silverlight40.Binding.TargetNullValueFallbackValue"  
           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"
           xmlns:navigation ="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"
           Title ="TargetNullValueFallbackValue Page" >
     < Grid  x:Name ="LayoutRoot" >
         < StackPanel  HorizontalAlignment ="Left"  Name ="stackPanel" >

             <!--
                FallbackValue - 当绑定失败（无法返回值）的时候所需要显示的值
             -->
             < TextBlock  Text =" {Binding Path=xxx, FallbackValue='绑定失败时的默认值'} "   />

             <!--
                TargetNullValue - 当绑定数据为 null 时所需要显示的值
             -->
             < TextBlock  Text =" {Binding TargetNullValue='绑定返回值为 null'} "   />

         </ StackPanel >
     </ Grid >
</ navigation:Page >

TargetNullValueFallbackValue.xaml.cs

代码

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  System.Windows.Navigation;

namespace  Silverlight40.Binding
{
     public   partial   class  TargetNullValueFallbackValue : Page
    {
         public  TargetNullValueFallbackValue()
        {
            InitializeComponent();
        }

         protected   override   void  OnNavigatedTo(NavigationEventArgs e)
        {
            stackPanel.DataContext  =   null ;
        }
    }
}

5、演示 CollectionViewSource 的应用
Product.cs

代码

using  System;
using  System.Net;
using  System.Windows;
using  System.Windows.Controls;
using  System.Windows.Documents;
using  System.Windows.Ink;
using  System.Windows.Input;
using  System.Windows.Media;
using  System.Windows.Media.Animation;
using  System.Windows.Shapes;

namespace  Silverlight40.Binding
{
     //  实体类
     public   class  Product
    {
         public   int  ProductId {  get ;  set ; }
         public   string  Name {  get ;  set ; }
         public   string  Category {  get ;  set ; }
    }
}

ProductCollection.cs

代码

using  System;
using  System.Net;
using  System.Windows;
using  System.Windows.Controls;
using  System.Windows.Documents;
using  System.Windows.Ink;
using  System.Windows.Input;
using  System.Windows.Media;
using  System.Windows.Media.Animation;
using  System.Windows.Shapes;

using  System.Collections.Generic;

namespace  Silverlight40.Binding
{
     public   class  ProductCollection : List < Product >
    {
        
    }
}

CollectionViewSource.xaml

代码 @H_404_1431@

< navigation:Page  x:Class ="Silverlight40.Binding.CollectionViewSource"  
           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"
           xmlns:navigation ="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"
           xmlns:sdk ="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"
           xmlns:c ="clr-namespace:System.ComponentModel;assembly=System.Windows"
           xmlns:local ="clr-namespace:Silverlight40.Binding"
           Title ="CollectionViewSource Page" >
     < Grid  x:Name ="LayoutRoot" >

         < Grid.Resources >
             < local:ProductCollection  x:Key ="products" >
                 < local:Product  ProductId ="1"  Name ="abc"  Category ="CategoryA"   />
                 < local:Product  ProductId ="2"  Name ="xyz"  Category ="CategoryA"   />
                 < local:Product  ProductId ="3"  Name ="webabcd"  Category ="CategoryB"   />
             </ local:ProductCollection >

             <!--
                CollectionViewSource - 实现了 ICollectionView 的类，可以通过它对数据排序、筛选和分组
                    CollectionViewSource.sortDescriptions - 指定排序方式
                        PropertyName - 指定排序的字段
                        Direction - 指定按升序还是降序排序
                    CollectionViewSource.GroupDescriptions - 指定分组方式
                        PropertyName - 指定分组的字段
                        StringComparison - 指定是否区分大小写等
             -->
             < CollectionViewSource  x:Name ="dataSource"  Source =" {StaticResource products} " >
                 < CollectionViewSource.sortDescriptions >
                     < c:SortDescription  PropertyName ="Name"  Direction ="Descending"   />
                 </ CollectionViewSource.sortDescriptions >
                 < CollectionViewSource.GroupDescriptions >
                     < PropertyGroupDescription  PropertyName ="Category"  StringComparison ="CurrentCultureIgnoreCase"   />
                 </ CollectionViewSource.GroupDescriptions >
             </ CollectionViewSource >
         </ Grid.Resources >

         < sdk:DataGrid  ItemsSource =" {Binding Source={StaticResource dataSource}} "   />

     </ Grid >
</ navigation:Page >

OK
[源码下载]