Silverlight 2学习教程（六）

在上一篇Blog文章中，讲述了JavaScript与Silverlight托管代码相互调用的一些方法。实际上，HtmlWindow的GetProperty方法和Invoke/InvokeSelf方法的返回值是Object类型的，代表 DOM对象或者JavaScript对象（HtmlDocument、HtmlElement、HtmlObject、ScriptObject）的返回值自动作为最接近的类型进行返回，但是，程序开发人员仍然需要明确地将该对象转换成相应的类型。所有的数字，由于跨浏览器的原因，都作为Double类型返回，如果需要Int32类型，则执行Convert.ToInt32()方法即可。

在现代的Web应用中，JSON的使用越来越频繁。Silverlight 2中要调用JavaScript中的JSON对象，首先在托管代码中声明一个类，类的属性与JSON对象的属性一致（不必完全一致），然后在托管代码中将ScriptObject对象转换成声明的这个类型即可。

下面是一个完整的例子：

Page.xaml：

<UserControl x:Class="SilverlightApplication1.Page"
xmlns="http://schemas.microsoft.com/client/2007"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Width="600" Height="480">
<Grid x:Name="LayoutRoot" Background="White">
<Canvas Canvas.Top="20">
<TextBlock Canvas.Top="10" Canvas.Left="20">请输入您的姓名： </TextBlock>
<TextBox x:Name="UserInput" Width="200" Height="30" Canvas.Top="40" Canvas.Left="20"></TextBox>
<TextBlock x:Name="Msg" Canvas.Top="90" Canvas.Left="20" Foreground="Navy" FontSize="18" Width="500"></TextBlock>
<Button Click="Button_Click" Content="单击我" FontSize="24" Width="160" Height="60" x:Name="BtnTest" Canvas.Top="160" Canvas.Left="20"></Button>
<Button Click="JSONButton_Click" Content="JavaScript JSON 对象测试" FontSize="24" Width="300" Height="50" Canvas.Top="240" Canvas.Left="20"></Button>
<TextBlock x:Name="Msg2" Canvas.Top="300" Canvas.Left="20" Foreground="Navy" FontSize="18" Width="500"></TextBlock>
<TextBlock x:Name="Msg3" Canvas.Top="320" Canvas.Left="20" Foreground="Navy" FontSize="18" Width="500"></TextBlock>
</Canvas>
</Grid>
</UserControl>

Page.xaml.cs：

using System;
using System.Collections.Generic;
using System.Linq;
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.Browser;
using System.Runtime.Serialization.Json;

namespace SilverlightApplication1
{
public partial class Page : UserControl
{
public Page()
{
InitializeComponent();
}

private void Button_Click(object sender, RoutedEventArgs e)
{
string UserInputContent = this.UserInput.Text;
if (UserInputContent.Equals(String.Empty))
{
UserInputContent = "Hello Silverlight World!";
}
else
{
UserInputContent = "你好，" + UserInputContent;
}
HtmlWindow win = HtmlPage.Window;
this.Msg.Text = UserInputContent;
win.Alert("Silverlight 里面弹出的对话框。 " + UserInputContent);
//执行页面中的js函数：
win.Eval("getArrayTest()");
Object[] args = { "将此参数传递给 js 函数" };
win.Invoke("getArrayTest", args);

//如果页面中的值
HtmlDocument doc = HtmlPage.Document;
doc.GetElementById("UserName").SetAttribute("value", this.UserInput.Text);
}

[ScriptableMember()]
public string InterInvole()
{
string username = HtmlPage.Document.GetElementById("UserName").GetAttribute("value");
this.UserInput.Text = username;
this.Msg.Text = "您输入了：" + username;
return "你从js脚本中调用了 Silverlight 里面的方法。";
}

private void JSONButton_Click(object sender, RoutedEventArgs e)
{
ScriptObject so = HtmlPage.Window.Invoke("ReturnObject", null) as ScriptObject;
Staple s = so.ConvertTo<Staple>();
this.Msg2.Text = "大家好，我在 JavaScript JSON 对象中的名称是：" + s.UserName;
}

//接受Html页面传递的 JSON 字符串
[ScriptableMember()]
public void ReveiveJSON(string jsonString)
{
//注意引用：System.Runtime.Serialization.Json

DataContractJsonSerializer json = new DataContractJsonSerializer(typeof(Staple));
System.IO.MemoryStream ms = new System.IO.MemoryStream(System.Text.Encoding.Unicode.GetBytes(jsonString));
Staple staple = new Staple();
staple = (Staple)json.ReadObject(ms);
Msg3.Text = "UserId = " + staple.UserId.ToString() + " ， UserName = " + staple.UserName;
}
}

public class Staple
{
public string UserName { set; get; }
public Double UserId { set; get; }
}
}

App.xaml.cs：

using System;
using System.Collections.Generic;
using System.Linq;
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.Browser;

namespace SilverlightApplication1
{
public partial class App : Application
{

public App()
{
this.Startup += this.Application_Startup;
this.Exit += this.Application_Exit;
this.UnhandledException += this.Application_UnhandledException;

InitializeComponent();
}

private void Application_Startup(object sender, StartupEventArgs e)
{
// Load the main control
Page p = new Page();
HtmlPage.RegisterScriptableObject("SilverlightApplicationExample", p);

// 请注意这里的定义方法，如果这里的p写成 new Page()，则Javascript基本不能给 UserInput 赋值！
this.RootVisual = p;
}

private void Application_Exit(object sender, EventArgs e)
{

}
private void Application_UnhandledException(object sender, ApplicationUnhandledExceptionEventArgs e)
{

}
}
}

SilverlightApplication1TestPage.aspx：

<%@ Page Language="C#" AutoEventWireup="true" %>

<%@ Register Assembly="System.Web.Silverlight" Namespace="System.Web.UI.SilverlightControls" TagPrefix="asp" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Silverlight 2托管代码与Javascript交互的例子</title>
<script type="text/javascript">
//<!{CDATA[
//定义全局变量：
var testVar = "孟宪会";

//定义全局函数：
function getArrayTest()
{
if(arguments.length > 0)
{
alert("js 对话框：您传递了参数。" + arguments[0]);
return arguments[0];
}
else
{
alert("js 对话框：无参数调用。");
return "js 函数返回值";
}
}

function SetUserName()
{
alert(SilverlightPlugin.Content.SilverlightApplicationExample.InterInvole());
}

var Staple = {
UserId:100,
UserName:'孟宪会',
SayHello:function(){alert(this.UserName)}
};

function ReturnObject()
{
return Staple;
}

function SendJSONToSilverlight()
{
SilverlightPlugin.Content.SilverlightApplicationExample.ReveiveJSON(JSON.stringify(Staple));
}

//定义Silverlight插件对象
var SilverlightPlugin = null;;
function pluginLoaded(sender)
{
SilverlightPlugin = sender.get_element();
}
//]]>
</script>
<script src="json2.js" type="text/javascript"></script>
<!-- http://www.JSON.org/json2.js -->
</head>
<body style="height: 100%; margin: 0;">
<form id="form1" runat="server">
<div style="border: 2px solid #EEE; margin: 20px;padding:20px">
请输入你的名字：<input id="UserName" type="text" value="" />
<input type="button" onclick="SetUserName()" value="将名字传递到 Silverlight" /> <input type="button" onclick="SendJSONToSilverlight()" value="将JSON传递到 Silverlight" />
</div>
<br />
<div style="border: 2px solid #EEE;margin: 20px;">
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:Silverlight ID="Xaml1" runat="server" OnPluginLoaded="pluginLoaded" Source="~/ClientBin/SilverlightApplication1.xap" Version="2.0" Width="600px" Height="480px" />
</div>
</form>
</body>
</html>

单击“JavaScript JSON 对象测试”按钮，运行结果如下：



原帖地址:http://blog.csdn.net/net_lover/archive/2008/04/06/2254267.aspx 感谢孟宪会老师