Silverlight中根据绑定内容动态生成模板

     最近在做Silverlight项目时，需要根据绑定的内容动态生成不同的模板。如是在网上找了下，发现这个不错，如是把例子总结了下。代码和注释如下。

(1)ObservableObject.cs类

//具有通知功能的ObservableObject的类 //其实可以将NotifyPropertyChanged写在City中，但这样以类的形式写更具有扩展性 public class ObservableObject : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; protected void NotifyPropertyChanged(object sender, String propertyName) { if (PropertyChanged != null) PropertyChanged(sender, new PropertyChangedEventArgs(propertyName)); } }

(2)City.cs类

//实体City public class City : ObservableObject { private string _Name; private string _Country; //城市名称 public string Name { get { return _Name; } set { if (_Name != value) { _Name = value; NotifyPropertyChanged(this, "Name"); } } } //国家名称 public string Country { get { return _Country; } set { if (_Country != value) { _Country = value; NotifyPropertyChanged(this, "Country"); } } } }

（3）DataTemplateSelector.cs类

public abstract class DataTemplateSelector : ContentControl { public virtual DataTemplate SelectTemplate(object item, DependencyObject container) { return null; } //重写OnContentChanged方法 protected override void OnContentChanged(object oldContent, object newContent) { base.OnContentChanged(oldContent, newContent); ContentTemplate = SelectTemplate(newContent, this); } }

（4）CountryTemplateSelector.cs类

public class CountryTemplateSelector : DataTemplateSelector { //定义Brazil,Usa,England三个不同国家模板 public DataTemplate BrazilTemplate { get; set; } public DataTemplate UsaTemplate { get; set; } public DataTemplate EnglandTemplate { get; set; } //由城市实体-->实体所在国家-->所在国家的模板 public override DataTemplate SelectTemplate( object item, DependencyObject container) { City itemAux = item as City; if (itemAux != null) { if (itemAux.Country == "Brazil") return BrazilTemplate; if (itemAux.Country == "USA") return UsaTemplate; if (itemAux.Country == "England") return EnglandTemplate; } return base.SelectTemplate(item, container); } }

（5）MainViewModel.cs类

//Cites属性 public ObservableCollection<City> Cities { get; set; } //数据集 public MainViewModel() { Cities = new ObservableCollection<City>(); Cities.Add(new City { Country = "Brazil", Name = "São Paulo" }); Cities.Add(new City { Country = "Brazil", Name = "Curitiba" }); Cities.Add(new City { Country = "Brazil", Name = "Rio de Janeiro" }); Cities.Add(new City { Country = "Brazil", Name = "Salvador" }); Cities.Add(new City { Country = "Brazil", Name = "Recife" }); Cities.Add(new City { Country = "USA", Name = "San Francisco" }); Cities.Add(new City { Country = "USA", Name = "Los Angeles" }); Cities.Add(new City { Country = "USA", Name = "New York" }); Cities.Add(new City { Country = "USA", Name = "Chicago" }); Cities.Add(new City { Country = "USA", Name = "Houston" }); Cities.Add(new City { Country = "England", Name = "London" }); } }

（6）MainPage.xaml

<UserControl x:Class="DataTemplateSelector.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" xmlns:local="clr-namespace:DataTemplateSelector" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400"> <Grid x:Name="LayoutRoot" Background="White"> <ListBox ItemsSource="{Binding Cities}" HorizontalContentAlignment="Stretch" x:Name="LB"> <ListBox.ItemTemplate> <DataTemplate> <local:CountryTemplateSelector Content="{Binding}"> <local:CountryTemplateSelector.BrazilTemplate> <DataTemplate> <Grid Background="Green"> <TextBlock Text="{Binding Name}"/> </Grid> </DataTemplate> </local:CountryTemplateSelector.BrazilTemplate> <local:CountryTemplateSelector.UsaTemplate> <DataTemplate> <Grid Background="Blue"> <TextBlock Text="{Binding Name}"/> </Grid> </DataTemplate> </local:CountryTemplateSelector.UsaTemplate> <local:CountryTemplateSelector.EnglandTemplate> <DataTemplate> <Grid Background="Red"> <TextBlock Text="{Binding Name}"/> </Grid> </DataTemplate> </local:CountryTemplateSelector.EnglandTemplate> </local:CountryTemplateSelector> </DataTemplate> </ListBox.ItemTemplate> </ListBox> </Grid></UserControl>

(7)MainPage.cs

public partial class MainPage : UserControl { public MainPage() { InitializeComponent(); this.Loaded += new RoutedEventHandler(MainPage_Loaded); } //根据MainPage.xaml中ListBox已设置好的三个国家的模板，绑定之后所属三个不同城市的名字都会 //加上不同国家的颜色了Brazil（Green）,Usa(Blue),England(Red) void MainPage_Loaded(object sender, RoutedEventArgs e) { LB.ItemsSource = new MainViewModel().Cities; } //总结：根据绑定的数据类容，动态选择不同的模板确实很有用，例如：我们要复用一个控件，而控件内容可能完全不一样，使用这种方法可以达到更具你要加载的内容来创建控件。 }

源码下载页面：http://download.csdn.net/source/2684599