Silverlight 2.0 正式版发布的后
在 HttpWebrequest 方面也发生了
些变化以前
代码正式版里面可能就无法运行了具体变化主要有:
1
在
HttpWebRequest.BeginGetResponse
的前Request 流必须关闭；2
HttpWebRequest.EndGetResponse 抛出异常正式版的前HttpWebRequest.BeingGetResponse 中跨域、跨协议访问抛出安全性异常其他请求都返回404
现在HttpRequest.EndGetResponse将作为异常抛出涉及安全问题抛出 SecurityException非成功请求会抛出 WebException 异常WebException.Response 被设置成 HttpStatusCode.NotFound由于 HttpWebrequest 发送
是异步请求如果要和界面交互还涉及到线程同步问题如果不进行线程同步会报告“跨线程访问无效”下面就以实际例子来向个 Java Servlet 地址提交数据将提交数据返回到当前界面中当然提交到 aspx 页面上也没有问题只需要在 Page_Load 事件处理思路方法里加入下面代码即可:查看复制到剪切板打印
protected void Page_Load(object sender, EventArgs e)
{
(Request.RequestType.Equals("POST"))
{
Response.ClearContent;
Response.ClearHeaders;
Response.Write("您提交数据是:" + Request.Params.Get("data"));
Response.End;
;
}
}如果提交到 Java Servlet
则测试代码可以写:查看复制到剪切板打印
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.getWriter.pr
("您提交数据是:" + request.getParameter("data"));
}要在本机进行跨域测试
需要在hosts文件进行设置如:127.0.0.1 www.mengxianhui.com
127.0.0.1 www.xianhuimeng.com
这样
就可以在你自己机器上进行跨域测试了不过需要记住默认情况下Silverlight 是不允许跨域访问因此需要在接收数据网站WebSite根目录下(记住是网站WebSite根目录不是应用
根目录)放置个策略文件clientaccesspolicy.xml 或者 crossdo
.xml :clientaccesspolicy.xml 内容设置如下:
查看复制到剪切板打印
<?xml version="1.0" encoding="utf-8"?>
<access-policy>
<cross-do-access>
<policy>
<allow-from http-request-headers="*">
<do uri="*" />
</allow-from>
<grant-to>
<resource path="/" 
-subpaths="true" />
</grant-to>
</policy>
</cross-do-access>
</access-policy>crossdo
.xml 内容设置如下:查看复制到剪切板打印
<?xml version="1.0"?>
<!DOCTYPE cross-do-policy SYSTEM "http://www.macromedia.com/xml/dtds/cross-do-policy.dtd">
<cross-do-policy>
<allow-http-request-headers-from do="*" headers="*"/>
</cross-do-policy>本例子中使用
Page.xaml 如下:查看复制到剪切板打印
<UserControl xmlns:basics="clr-
:
.Windows.Controls;assembly=.Windows.Controls"
x:Class="SilverlightApplication3.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">
<Canvas Width="400" Height="300" Canvas.Left="2">
<TextBox x:Name="data" Canvas.Left="2" Canvas.Top="2" Height="30" Width="180" Text="【孟子E章】测试数据" F></TextBox>
<Button C Width="100" Height="30" Click="PostData" Canvas.Top="2" Canvas.Left="200"></Button>
<TextBlock x:Name="result" Canvas.Top="40" F></TextBlock>
</Canvas>
</Grid>
</UserControl>Page.xaml.cs 完整内容
查看复制到剪切板打印
using ;
using .Collections.Generic;
using .Linq;
using .Net;
using .Windows;
using .Windows.Controls;
using .Windows.Documents;
using .Windows.Input;
using .Windows.Media;
using .Windows.Media.Animation;
using .Windows.Shapes;
using .Text;
using .IO;
using .Diagnostics;
using .Threading;
SilverlightApplication3
{
public partial 
Page : UserControl
{
public Page
{
InitializeComponent;
//设置当前界面线程
syncContext = SynchronizationContext.Current;
}
private SynchronizationContext syncContext;
private String postData = String.Empty;
private void PostData(object sender, RoutedEventArgs e)
{
//请注意:Silverlight 里 HttpWebRequest, Encoding 类属性和思路方法和常规 .NET Framework 里面还是区别
result.Text = "开始提交数据……";
postData = "data=" + data.Text; //要提交内容
Uri url = 
Uri("http://www.mengxianhui.com/admin?tmp=" + DateTime.Now.Ticks.
, UriKind.Absolute);
.Net.HttpWebRequest request = (.Net.HttpWebRequest)WebRequest.Create(url);
request.Method = "POST"; // Silverlight 只支持 GET 和 POST 思路方法
request.AllowReadStreamBuffering = true;
request.C;
request.BeginGetRequestStream( AsyncCallback(RequestReady), request);
}
private void RequestReady(IAsyncResult asyncResult)
{
HttpWebRequest request = asyncResult.AsyncState as HttpWebRequest;
StreamWriter postStream = StreamWriter(request.EndGetRequestStream(asyncResult));
//
Array = Encoding.UTF8.GetBytes(postData);
//Encoding.GetEncoding思路方法只支持 4种编码utf-8 , utf-16 , utf-16BE , utf-16LE
postStream.Write(postData); //处理中文问题不要使用 Stream Write 思路方法
postStream.Close;
postStream.Dispose;
request.BeginGetResponse( AsyncCallback(ResponseReady), request);
}
void ResponseReady(IAsyncResult asyncResult)
{
HttpWebRequest request = asyncResult.AsyncState as HttpWebRequest;
WebResponse response = request.EndGetResponse(asyncResult) as WebResponse;
//同步线程上下文
(syncContext 
null) syncContext = SynchronizationContext;
syncContext.Post(ExtractResponse, response);
}
private void ExtractResponse(object state)
{
WebResponse response = state as WebResponse;
Stream responseStream = response.GetResponseStream;
StreamReader streamRead = StreamReader(responseStream);
//显示返回数据
result.Text = StreamReader(responseStream).ReadToEnd;
response.Close;
responseStream.Close;
responseStream.Dispose;
streamRead.Close;
streamRead.Dispose;
}
}
}
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