有一篇技巧,见
或
讨论的是运用InitParams在Silverlight 2应用程序中切换用户控件,这是个很笨但是直观的解决方式。
但如果在控件中传值，那将怎么办？以上方法将毫无用途！
今天在一个老外的博客看到有个很巧妙的方法，不敢独享，现分享出来：
首先写个接口：
namespace PageSwitchSimple{ public interface ISwitchable { void UtilizeState( object state ); }}
然后写个切换类：
using System.Windows.Controls;
namespace PageSwitchSimple
{ public static class Switcher { public static PageSwitcher pageSwitcher;public static void Switch( UserControl newPage )
{ pageSwitcher.Navigate( newPage ); }public static void Switch( UserControl newPage, object state )
{ pageSwitcher.Navigate( newPage, state ); } }}
PageSwitcher 成员类：
前台代码：
<UserControl x:Class="PageSwitchSimple.PageSwitcher"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Width="800" Height="600"></UserControl>
后台代码：
using System;
using System.Windows.Controls;namespace PageSwitchSimple
{ public partial class PageSwitcher : UserControl { public PageSwitcher() { InitializeComponent(); }public void Navigate( UserControl nextPage )
{ this.Content = nextPage; }public void Navigate( UserControl nextPage, object state )
{ this.Content = nextPage; ISwitchable s = nextPage as ISwitchable;//这里真是太巧妙了，用于传object 参数！
if ( s != null ) { s.UtilizeState( state ); } else { throw new ArgumentException( "nextPage is not ISwitchable! " + nextPage.Name.ToString() ); } } }}然后写两个实现接口ISwitchable的用户控件：
控件一：
<UserControl x:Class="PageSwitchSimple.Page"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Width="400" Height="300"> <Grid x:Name="LayoutRoot" Background="White"> <TextBlock Text="Your Name: " FontSize="18" /> <TextBox x:Name="Name" FontSize="18" Width="150" Height="35" VerticalAlignment="Top" Margin="5"/> <Button x:Name="ChangePage" Content="Change" FontSize="18" Width="100" Height="50" /> </Grid></UserControl>后台代码：
using System.Windows;
using System.Windows.Controls;namespace PageSwitchSimple
{ public partial class Page : UserControl, ISwitchable { public Page() { InitializeComponent(); ChangePage.Click += new RoutedEventHandler( ChangePage_Click ); }void ChangePage_Click( object sender, RoutedEventArgs e )
{ Switcher.Switch( new Page2(), Name.Text ); } }}
控件二：
<UserControl x:Class="PageSwitchSimple.Page2"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Width="400" Height="300"> <Grid x:Name="LayoutRoot" Background="Bisque"> <TextBlock x:Name="Message" Text="Page2" FontSize="18" /> <Button x:Name="ChangePage" Content="Change" FontSize="18" Width="100" Height="50" /> </Grid></UserControl>后台代码：
using System.Windows;
using System.Windows.Controls;namespace PageSwitchSimple
{ public partial class Page2 : UserControl, ISwitchable { public Page2() { InitializeComponent(); ChangePage.Click += new RoutedEventHandler( ChangePage_Click ); }public void UtilizeState( object state )
{ Message.Text = state.ToString(); }void ChangePage_Click( object sender, RoutedEventArgs e )
{ Switcher.Switch( new Page() ); } }}
最后修改App.cs
private void Application_Startup( object sender, StartupEventArgs e )
{ PageSwitcher pageSwitcher = new PageSwitcher(); this.RootVisual = pageSwitcher; Switcher.pageSwitcher = pageSwitcher; Switcher.Switch( new Page() ); }
巧妙运用了观察者模式，佩服作者的思路。