Silverlight文件上传下载实现方法(下载保存)

search了非常多的文章，总算勉强实现了。有许多不完善的地方。

在HCLoad.Web项目下新建目录Pics复制一张图片到根目录下。

图片名：Bubble.jpg 右击->属性->生成操作：Resource

UC_UpDown.xaml

<UserControl x:Class="HCLoad.UC_UpDown"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Width="500" Height="500">
<StackPanel Background="White" Height="450">
<Button Content="down" Click="Button_Click"></Button>
<HyperlinkButton Content="下载保存" NavigateUri="http://localhost:4528/download.ashx?fileName=aa.txt" TargetName="_self" x:Name="lBtnDown" />
<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>

UC_UpDown.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.Windows.Media.Imaging; //因为要使用BitmapImage
using System.IO; //因为要使用Stream
namespace HCLoad
{
public partial class UC_UpDown : UserControl
{
//1、WebClient 对象一次只能启动一个请求。如果在一个请求完成（包括出错和取消）前，即IsBusy为true时，进行第二个请求，则第二个请求将会抛出 NotSupportedException 类型的异常
//2、如果 WebClient 对象的 BaseAddress 属性不为空，则 BaseAddress 与 URI（相对地址） 组合在一起构成绝对 URI
//3、WebClient 类的 AllowReadStreamBuffering 属性：是否对从 Internet 资源接收的数据做缓冲处理。默认值为true，将数据缓存在客户端内存中，以便随时被应用程序读取
//获取选定图片信息
System.IO.FileInfo fileinfo;
public UC_UpDown()
{
InitializeComponent();
}
#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:4528/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.Error != null)
{
MessageBox.Show(e.Error.ToString());
return;
}
if (e.Cancelled != true)
{
//获取下载的流数据(在此处是图片数据)并显示在图片控件中
//Stream stream = e.Result;
//BitmapImage bitmap = new BitmapImage();
//bitmap.SetSource(stream);
//imgDownLoad.Source = bitmap;
Stream clientStream = e.UserState as Stream;
Stream serverStream = (Stream)e.Result;
byte[] buffer = new byte[serverStream.Length];
serverStream.Read(buffer, 0, buffer.Length);
clientStream.Write(buffer, 0, buffer.Length);
clientStream.Close();
serverStream.Close();
}
}
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
this.tbMsgString.Text = string.Format("完成百分比：{0} 当前收到的字节数：{1} 资料大小：{2} ",
e.ProgressPercentage.ToString() + "%",
e.BytesReceived.ToString(),
e.TotalBytesToReceive.ToString());
}
#endregion
#region 上传图片
private void btnUpLoad_Click(object sender, RoutedEventArgs e)
{
/**/
/*
*　　 OpenWriteCompleted - 在打开用于上传的流完成时（包括取消操作及有错误发生时）所触发的事件
*　　 WriteStreamClosed - 在写入数据流的异步操作完成时（包括取消操作及有错误发生时）所触发的事件
*　　 UploadProgressChanged - 上传数据过程中所触发的事件。如果调用 OpenWriteAsync() 则不会触发此事件
*　　 Headers - 与请求相关的的标头的 key/value 对**
*　　 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
*　　　　 Uri address - 接收上传数据的 URI
*　　　　 string method - 所使用的 HTTP 方法（POST 或 GET）
*　　　　 Object userToken - 需要上传的数据流
*/
OpenFileDialog openFileDialog = new OpenFileDialog()
{ //弹出打开文件对话框要求用户自己选择在本地端打开的图片文件
Filter = "Jpeg Files (*.jpg)|*.jpg|All Files(*.*)|*.*",
Multiselect = false //不允许多选
};
if (openFileDialog.ShowDialog() == true)//.DialogResult.OK)
{
//fileinfo = openFileDialog.Files; //取得所选择的文件，其中Name为文件名字段，作为绑定字段显示在前端
fileinfo = openFileDialog.File;
if (fileinfo != null)
{
WebClient webclient = new WebClient();
string uploadFileName = fileinfo.Name.ToString(); //获取所选文件的名字
#region 把图片上传到服务器上
Uri upTargetUri = new Uri(String.Format("http://localhost:4528/WebClientUpLoadStreamHandler.ashx?fileName={0}", uploadFileName), UriKind.Absolute); //指定上传地址
webclient.OpenWriteCompleted += new OpenWriteCompletedEventHandler(webclient_OpenWriteCompleted);
webclient.Headers["Content-Type"] = "multipart/form-data";
webclient.OpenWriteAsync(upTargetUri, "POST", fileinfo.OpenRead());
webclient.WriteStreamClosed += new WriteStreamClosedEventHandler(webclient_WriteStreamClosed);
#endregion
}
else
{
MessageBox.Show("请选取想要上载的图片!!!");
}
}
}
void webclient_OpenWriteCompleted(object sender, OpenWriteCompletedEventArgs e)
{
//将图片数据流发送到服务器上
// e.UserState - 需要上传的流（客户端流）
Stream clientStream = e.UserState as Stream;
// e.Result - 目标地址的流（服务端流）
Stream serverStream = e.Result;
byte[] buffer = new byte[4096];
int readcount = 0;
// clientStream.Read - 将需要上传的流读取到指定的字节数组中
while ((readcount = clientStream.Read(buffer, 0, buffer.Length)) > 0)
{
// serverStream.Write - 将指定的字节数组写入到目标地址的流
serverStream.Write(buffer, 0, readcount);
}
serverStream.Close();
clientStream.Close();
}
void webclient_WriteStreamClosed(object sender, WriteStreamClosedEventArgs e)
{
//判断写入是否有异常
if (e.Error != null)
{
System.Windows.Browser.HtmlPage.Window.Alert(e.Error.Message.ToString());
}
else
{
System.Windows.Browser.HtmlPage.Window.Alert("图片上传成功!!!");
}
}
#endregion
private void Button_Click(object sender, RoutedEventArgs e)
{
//这种方法搞不定，好像提示跨域操作。
//提示：错误：Unhandled Error in Silverlight Application 跨线程访问无效。
//Uri upTargetUri = new Uri(String.Format("http://localhost:4528/download.ashx?filename={0}", "123.jpg"), UriKind.Absolute); //指定上传地址
//WebRequest request = WebRequest.Create(upTargetUri);
//request.Method = "GET";
//request.ContentType = "application/octet-stream";
//request.BeginGetResponse(new AsyncCallback(RequestReady), request);
//通过调用js代码下载，比较简单。
System.Windows.Browser.HtmlPage.Window.Eval("window.location.href='http://localhost:4528/download.ashx?filename=123.jpg';");
}
void RequestReady(IAsyncResult asyncResult)
{
MessageBox.Show("RequestComplete");
}
}
}

在HCLoad.Web项目下新建WebClientUpLoadStreamHandler.ashx

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.IO; //因为要用到Stream
namespace HCLoad.Web
{
public class WebClientUpLoadStreamHandler : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
//获取上传的数据流
string fileNameStr = context.Request.QueryString["fileName"];
Stream sr = context.Request.InputStream;
try
{
string filename = "";
filename = fileNameStr;
byte[] buffer = new byte[4096];
int bytesRead = 0;
//将当前数据流写入服务器端文件夹ClientBin下
string targetPath = context.Server.MapPath("Pics/" + filename + ".jpg");
using (FileStream fs = File.Create(targetPath, 4096))
{
while ((bytesRead = sr.Read(buffer, 0, buffer.Length)) > 0)
{
//向文件中写信息
fs.Write(buffer, 0, bytesRead);
}
}
context.Response.ContentType = "text/plain";
context.Response.Write("上传成功");
}
catch (Exception e)
{
context.Response.ContentType = "text/plain";
context.Response.Write("上传失败, 错误信息:" + e.Message);
}
finally
{ sr.Dispose(); }
}
public bool IsReusable
{
get
{
return false;
}
}
}
}

新建download.ashx

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Net;
namespace HCLoad.Web
{
/// <summary>
/// $codebehindclassname$ 的摘要说明
/// </summary>
public class download : IHttpHandler
{
private long ChunkSize = 102400;//100K 每次读取文件，只读取100Ｋ，这样可以缓解服务器的压力
public void ProcessRequest(HttpContext context)
{
//string fileName = "123.jpg";//客户端保存的文件名
String fileName = context.Request.QueryString["filename"];
string filePath = context.Server.MapPath("Bubble.jpg");
System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath);
if (fileInfo.Exists == true)
{
byte[] buffer = new byte[ChunkSize];
context.Response.Clear();
System.IO.FileStream iStream = System.IO.File.OpenRead(filePath);
long dataLengthToRead = iStream.Length;//获得下载文件的总大小
context.Response.ContentType = "application/octet-stream";
//通知浏览器下载文件而不是打开
context.Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));
while (dataLengthToRead > 0 && context.Response.IsClientConnected)
{
int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小
context.Response.OutputStream.Write(buffer, 0, lengthRead);
context.Response.Flush();
dataLengthToRead = dataLengthToRead - lengthRead;
}
context.Response.Close();
context.Response.End();
}
//context.Response.ContentType = "text/plain";
//context.Response.Write("Hello World");
}
public bool IsReusable
{
get
{
return false;
}
}
}
}

参考：
https://www.geek-share.com/detail/2462246781.html
https://www.geek-share.com/detail/2462174060.html
https://www.geek-share.com/detail/2447355500.html
http://topic.csdn.net/u/20090918/10/5e41ab52-f514-46b5-ae6a-d69ddb197213.html
https://www.geek-share.com/detail/2462174060.html
https://www.geek-share.com/detail/2449637361.html
https://www.geek-share.com/detail/2471421500.html
http://blog.csdn.net/emily1900/archive/2010/06/08/5655726.aspx