稳扎稳打Silverlight(20) - 2.0通信之WebClient, 以字符串的形式上传/下载数据, 以流的方式上传/下载数据...

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稳扎稳打Silverlight(20) - 2.0通信之WebClient, 以字符串的形式上传/下载数据, 以流的方式上传/下载数据

作者： webabcd


介绍
Silverlight 2.0 详解WebClient，以字符串的形式上传、下载数据；以流的方式上传、下载数据
    WebClient - 将数据发送到指定的 URI，或者从指定的 URI 接收数据的类
        DownloadStringAsync(Uri address, Object userToken) - 以字符串的形式下载指定的 URI 的资源
        UploadStringAsync(Uri address, string data) - 以字符串的形式上传数据到指定的 URI。所使用的 HTTP 方法默认为 POST
        OpenReadAsync(Uri address, Object userToken) - 以流的形式下载指定的 URI 的资源
        OpenWriteAsync(Uri address, string method, Object userToken) - 打开流以使用指定的方法向指定的 URI 写入数据


在线DEMO
http://webabcd.blog.51cto.com/1787395/342779  


示例
1、以字符串的形式和流的形式下载数据
WebClientDownload.xaml

<UserControl x:Class="Silverlight20.Communication.WebClientDownload"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
        <StackPanel HorizontalAlignment="Left" Orientation="Horizontal">
        
                <StackPanel Margin="5" Width="200">
                        <TextBox x:Name="lblMsgString" Margin="5" />
                        <ProgressBar x:Name="progressBarString" Height="20" Margin="5" Minimum="0" Maximum="100" />
                </StackPanel>
                
                <StackPanel Margin="5" Width="200">
                        <TextBox x:Name="lblMsgStream" Margin="5" />
                        <ProgressBar x:Name="progressBarStream" Height="20" Margin="5" Minimum="0" Maximum="100" />
                        <Image x:Name="img" Margin="5" />
                </StackPanel>
                
        </StackPanel>
</UserControl>

 

WebClientDownload.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
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.IO;

namespace Silverlight20.Communication
{
         public partial class WebClientDownload : UserControl
        {
                 // 用于演示以字符串的形式下载数据
                 string _urlString = "http://localhost/Files/Demo.zip";

                // 用于演示以流的形式下载数据
                string _urlStream = "http://localhost/Files/Logo.png";

                public WebClientDownload()
                {
                        InitializeComponent();

                        // 演示字符串式下载
                        DownloadStringDemo();

                        // 演示流式下载
                        DownloadStreamDemo();
                }

                /// <summary>
                /// 演示字符串式下载
                /// </summary>
                void DownloadStringDemo()
                {
                        Uri uri = new Uri(_urlString, UriKind.Absolute);

                        /*    
                         * WebClient - 将数据发送到指定的 URI，或者从指定的 URI 接收数据的类
                         *         DownloadStringCompleted - 下载数据完毕后（包括取消操作及有错误发生时）所触发的事件
                         *         DownloadProgressChanged - 下载数据过程中所触发的事件。正在下载或下载完全部数据后会触发
                         *         DownloadStringAsync(Uri address, Object userToken) - 以字符串的形式下载指定的 URI 的资源
                         *                 Uri address - 需要下载的资源地址
                         *                 Object userToken - 用户标识
                         */

                        System.Net.WebClient clientDownloadString = new System.Net.WebClient();

                        clientDownloadString.DownloadStringCompleted += new DownloadStringCompletedEventHandler(clientDownloadString_DownloadStringCompleted);
                        clientDownloadString.DownloadProgressChanged += new DownloadProgressChangedEventHandler(clientDownloadString_DownloadProgressChanged);
                        clientDownloadString.DownloadStringAsync(uri, "userToken");
                }

                void clientDownloadString_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
                {
                        /*
                         * DownloadProgressChangedEventArgs.ProgressPercentage - 下载完成的百分比
                         * DownloadProgressChangedEventArgs.BytesReceived - 当前收到的字节数
                         * DownloadProgressChangedEventArgs.TotalBytesToReceive - 总共需要下载的字节数
                         * DownloadProgressChangedEventArgs.UserState - 用户标识
                         */

                        lblMsgString.Text = string.Format("下载完成的百分比：{0}\r\n当前收到的字节数：{1}\r\n总共需要下载的字节数：{2}\r\n",
                                e.ProgressPercentage.ToString() + "%",
                                e.BytesReceived.ToString(),
                                e.TotalBytesToReceive.ToString());

                        progressBarString.Value = (double)e.ProgressPercentage;
                }

                void clientDownloadString_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
                {
                        /*
                         * DownloadStringCompletedEventArgs.Error - 该异步操作期间是否发生了错误
                         * DownloadStringCompletedEventArgs.Cancelled - 该异步操作是否已被取消
                         * DownloadStringCompletedEventArgs.Result - 下载后的字符串类型的数据
                         * DownloadStringCompletedEventArgs.UserState - 用户标识
                         */

                        if (e.Error != null)
                        {
                                lblMsgString.Text += e.Error.ToString();
                                return;
                        }

                        if (e.Cancelled != true)
                        {
                                lblMsgString.Text += string.Format("用户标识：{0}", e.UserState.ToString());
                        }
                }



                /// <summary>
                /// 演示流式下载
                /// </summary>
                void DownloadStreamDemo()
                {
                        Uri uri = new Uri(_urlStream, UriKind.Absolute);

                        /*    
                         * WebClient - 将数据发送到指定的 URI，或者从指定的 URI 接收数据的类
                         *         IsBusy - 指定的web请求是否正在进行中
                         *         CancelAsync() - 取消指定的异步操作    
                         *         OpenReadCompleted - 数据读取完毕后（包括取消操作及有错误发生时）所触发的事件。流的方式
                         *         DownloadProgressChanged - 下载数据过程中所触发的事件。正在下载或下载完全部数据后会触发
                         *         OpenReadAsync(Uri address, Object userToken) - 以流的形式下载指定的 URI 的资源
                         *                 Uri address - 需要下载的资源地址
                         *                 Object userToken - 用户标识
                         */

                        System.Net.WebClient clientDownloadStream = new System.Net.WebClient();

                        if (clientDownloadStream.IsBusy)
                                clientDownloadStream.CancelAsync();

                        clientDownloadStream.OpenReadCompleted += new OpenReadCompletedEventHandler(clientDownloadStream_OpenReadCompleted);
                        clientDownloadStream.DownloadProgressChanged += new DownloadProgressChangedEventHandler(clientDownloadStream_DownloadProgressChanged);
                        clientDownloadStream.OpenReadAsync(uri);
                }

                void clientDownloadStream_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
                {
                        /*
                         * DownloadProgressChangedEventArgs.ProgressPercentage - 下载完成的百分比
                         * DownloadProgressChangedEventArgs.BytesReceived - 当前收到的字节数
                         * DownloadProgressChangedEventArgs.TotalBytesToReceive - 总共需要下载的字节数
                         * DownloadProgressChangedEventArgs.UserState - 用户标识
                         */

                        lblMsgString.Text = string.Format("下载完成的百分比：{0}\r\n当前收到的字节数：{1}\r\n总共需要下载的字节数：{2}\r\n",
                                e.ProgressPercentage.ToString() + "%",
                                e.BytesReceived.ToString(),
                                e.TotalBytesToReceive.ToString());

                        progressBarStream.Value = (double)e.ProgressPercentage;
                }

                void clientDownloadStream_OpenReadCompleted(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.Error != null)
                        {
                                lblMsgStream.Text += e.Error.ToString();
                                return;
                        }

                        if (e.Cancelled != true)
                        {
                                System.Windows.Media.Imaging.BitmapImage p_w_picpathSource = new System.Windows.Media.Imaging.BitmapImage();
                                p_w_picpathSource.SetSource(e.Result);
                                img.Source = p_w_picpathSource;
                        }
                }
        }
}

 

 

 

未完待续>>

 

 

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转载于:https://blog.51cto.com/webabcd/343127