SilverLight学习笔记--使用WebClient实现通讯(二)(上传和下载流数据).docx

?? 接上节，本文直接进入实例操作部分。在此处，我们以典型的图片文件为例来学习如何用WebClient类来实现上传和下载流数据的。?? 新建一个Silverlight应用程序，命名为:SLWebClientStream。?? 一、准备工作:?? 1、准备一张图片，本例我们准备了一张名为Bubble.jpg的图片，把它拷贝到SLWebClientStream.Web项目的根目录下。?? 2、在SLWebClientStream.Web项目下新建一个目录，命名为Pics，我们将在此处放置上传上来的图片文件。?? 完成准备工作后，项目如下图:????????????????????????????二、编码实现??(一)、客户端部分?1、建立用户界面?Page.xaml内容如下:?UserControl?x:Class=SLWebClientStream.Page????xmlns=/winfx/2006/xaml/presentation?????xmlns:x=/winfx/2006/xaml?????Width=500?Height=450????StackPanel?Background=White?Height=450????????TextBlock?x:Name=tbMsgString?Text=下载进度?TextAlignment=Center?Foreground=Green/TextBlock????????Button?x:Name=btnDownload?Content=DownLoad?Pictures?Width=150?Height=35?Margin=15?Click=btnDownload_Click/????????Border?Background=Wheat?BorderThickness=5?Width=400?Height=280????????????Image?x:Name=imgDownLoad?Width=400?Height=300?Margin=15?Stretch=Fill/????????/Border????????Button?x:Name=btnUpLoad?Content=UpLoad?Pictures?Width=150?Height=35?Margin=15?Click=btnUpLoad_Click/????/StackPanel/UserControl?界面如下:?????????????????????????2、下载图片文件代码????????#region??下载图片????????private?void?btnDownload_Click(object?sender,?RoutedEventArgs?e)????????{????????????//向指定的Url发送下载流数据请求?????????????String?imgUrl?=?http://localhost:51896/Bubble.jpg;??????????????????Uri?endpoint?=?new?Uri(imgUrl);????????????WebClient?client?=?new?WebClient();????????????client.OpenReadCompleted?+=?new?OpenReadCompletedEventHandler(OnOpenReadCompleted);????????????client.DownloadProgressChanged?+=?new?DownloadProgressChangedEventHandler(clientDownloadStream_DownloadProgressChanged);????????????client.OpenReadAsync(endpoint);????????}????????void?OnOpenReadCompleted(object?sender,OpenReadCompletedEventArgs?e)????????{??????????????//OpenReadCompletedEventArgs.Error?-?该异步操作期间是否发生了错误?????????????//OpenReadCompletedEventArgs.Cancelled?-?该异步操作是否已被取消?????????????//OpenReadCompletedEventArgs.Result?-?下载后的?Stream?类型的数据?????????????//OpenReadCompletedEventArgs.UserState?-?用户标识?????????????if?(e.Er