asp.net中Silverlight实现文件上传与下载

作者：袖梨 2022-06-25

文件下载通常采用附件的方式在http响应头里面设置Content-disposition值为"attachment;filename=" + filepath，以及为Content-Length设置下载文件总长度(单位字节)来实现。
本文是采用Silverlight实现文件下载,服务端用asp.net一般处理程序(.ashx)处理。
以下是项目结构图:

MainPage类源码如下:

 代码如下 复制代码

View Code
 namespace SilverlightDownAndUploadFile
 {
     public delegate void SaveFileHandler(int bytesRead, byte[] buffer);
     public delegate void UploadFileHandler(int bytesRead);
     public partial class MainPage : UserControl
     {
         private SaveFileDialog sfd;
         private OpenFileDialog ofd;
         Stream stream = null;
         BinaryWriter bw = null;
         private long fileLen = 0;
         private long readFileLen = 0;//已下载长度
         private AutoResetEvent autoEvent = new AutoResetEvent(false);
 
         public MainPage()
         {
             InitializeComponent();
         }
 
         #region 下载
         private void ShowDownResult(bool isSuccess)
         {
             this.Dispatcher.BeginInvoke(
                 () =>
                 {
                     if (isSuccess)
                         MessageBox.Show("下载完毕.");
                     else
                         MessageBox.Show("下载出错!");
                 });
         }
 
         private void UpdateDownProgress(int bytesRead)
         {
             readFileLen += bytesRead;
 
             double rate = Convert.ToDouble(readFileLen) / Convert.ToDouble(fileLen);
             double percent = Math.Round(rate, 2) * 100;
             downProgress.Visibility = Visibility.Visible;
             downProgress.pgBar.Value = percent;
             downProgress.txtProgress.Text = percent + "%";
 
         }
 
         private void FlushToFile(int bytesRead, byte[] buffer)
         {
             try
             {
                 if (null == stream)
                 {
                     stream = sfd.OpenFile();
                     bw = new BinaryWriter(stream);
                 }
 
                 bw.Write(buffer, 0, bytesRead);
                 bw.Flush();
                 UpdateDownProgress(bytesRead);
                 autoEvent.Set();
             }
             catch (Exception ex)
             { }
         }
 
         private void RequestAndDownFile()
         {
             try
             {
                 HttpWebRequest request = CreateWebRequest("http://localhost:13953/Download.ashx", "GET");
                 HttpWebRequest webRequest = request;
                 webRequest.BeginGetResponse(
                             (asyncResult) =>
                             {
                                 if (webRequest.HaveResponse)
                                 {
                                     try
                                     {
                                         WebResponse response = webRequest.EndGetResponse(asyncResult);//易发生异常
                                         fileLen = Convert.ToInt64(response.Headers["Content-Length"]);//文件长度
 
                                         Stream responseStream = response.GetResponseStream();
                                         int maxBufLength = 20 * 1024;//20K
                                         byte[] buffer = new byte[maxBufLength];
                                         int bytesRead = responseStream.Read(buffer, 0, maxBufLength);
                                         while (bytesRead != 0)
                                         {
                                             Dispatcher.BeginInvoke(new SaveFileHandler(FlushToFile), bytesRead, buffer);
                                             autoEvent.WaitOne();
                                             buffer = new byte[maxBufLength];
                                             bytesRead = responseStream.Read(buffer, 0, maxBufLength);
                                         }
 
                                         ShowDownResult(true);
                                     }
                                     catch (Exception ex)
                                     {
                                         ShowDownResult(false);
                                     }
                                     finally
                                     {
                                         this.Dispatcher.BeginInvoke(
                                             () =>
                                             {
                                                 if (null != bw)
                                                     bw.Close();
                                                 if (null != stream)
                                                     stream.Close();
                                             });
                                     }
                                 }
                             }, null);
 
             }
             catch (Exception ex)
             {
                 ShowDownResult(false);
             }
         }
 
         private void btnDownload_Click(object sender, RoutedEventArgs e)
         {
             fileLen = 0;
             readFileLen = 0;
             sfd = new SaveFileDialog();
             sfd.Filter = "(*.rar)|*.rar";
 
             if (sfd.ShowDialog() == true)
             {
                 RequestAndDownFile();
             }
         }
 
         private static HttpWebRequest CreateWebRequest(string requestUriString, string httpMethod)
         {
             try
             {
                 string ticks = Guid.NewGuid().ToString();
                 requestUriString = requestUriString + "/" + ticks;
                 HttpWebRequest request = (HttpWebRequest)WebRequestCreator.ClientHttp.Create(new Uri(requestUriString));
                 request.Method = httpMethod;
 
                 return request;
             }
             catch (Exception ex)
             {
                 return null;
             }
         }
         #endregion
 
         ///


         /// 获了实际接读取到的字节数组
         ///
         ///
         ///
         ///
         private byte[] GetNewBuffer(byte[] buffer, int bytesRead)
         {
             byte[] newBuffer = new byte[bytesRead];
             for (int i = 0; i < bytesRead; i++)
             {
                 newBuffer[i] = buffer[i];
             }
             return newBuffer;
         }
     }

Download.ashx源码如下：

 代码如下 复制代码

View Code
 namespace SilverlightDownAndUploadFile.Web
 {
     ///


     /// Download 的摘要说明
     ///
     public class Download : IHttpHandler
     {
 
         public void ProcessRequest(HttpContext context)
         {
             try
             {
                 //context.Response.ContentType = "text/plain";
                 //context.Response.Write("Hello World");
                 //要下载文件路径
                 string path = "d:/test.rar"; //context.Server.MapPath("~/Files/lan.txt");
                 context.Response.ContentType = Utils.GetContentType(path);//设置ContentType
                 context.Response.AppendHeader("Content-disposition", "attachment;filename=" + path);
                 context.Response.BufferOutput = false;
                 context.Response.Buffer = false;
                 using (FileStream fs = File.OpenRead(path))
                 {
                     BinaryReader br = new BinaryReader(fs);
                     long fileLen = br.BaseStream.Length;
                     context.Response.AppendHeader("Content-Length", fileLen.ToString());
 
                     int bytesRead = 0;//读取到的字节数
                     int maxBufLength = 20 * 1024;//20K
                     byte[] buffer = new byte[maxBufLength];
                     bytesRead = br.Read(buffer, 0, maxBufLength);
                     while (bytesRead != 0)
                     {
                         byte[] newBuffer = GetNewBuffer(buffer, bytesRead);
                         context.Response.BinaryWrite(newBuffer);
                         context.Response.Flush();
                         buffer = new byte[maxBufLength];
                         bytesRead = br.Read(buffer, 0, maxBufLength);
                     }
                     context.Response.Flush();
                     context.Response.End();
                 }
             }
             catch (Exception ex)
             {
 
             }
         }
 
         ///
         /// 获了实际接读取到的字节数组
         ///
         ///
         ///
         ///
         private byte[] GetNewBuffer(byte[] buffer, int bytesRead)
         {
             byte[] newBuffer = new byte[bytesRead];
             for (int i = 0; i < bytesRead; i++)
             {
                 newBuffer[i] = buffer[i];
             }
             return newBuffer;
         }
 
         public bool IsReusable
         {
             get
             {
                 return false;
             }
         }
     }
 }

文件上传

通过web进行文件上传，一般要使用form表单，在silverlight里面没有内置form表单功能，参考牛人文章，实现Silverlight文件上传。只要Web.config文件中httpRuntime节点的maxRequestLength属性足够大，上传就不受限制。

项目结构图：


MainPage类源码:

 代码如下 复制代码

View Code
 namespace SilverlightDownAndUploadFile
 {
     public partial class MainPage : UserControl
     {
         private OpenFileDialog ofd;
         private AutoResetEvent autoEvent = new AutoResetEvent(false);
 
         public MainPage()
         {
             InitializeComponent();
         }
 
         private static HttpWebRequest CreateWebRequest(string requestUriString, string httpMethod)
         {
             try
             {
                 string ticks = Guid.NewGuid().ToString();
                 requestUriString = requestUriString + "/" + ticks;
                 HttpWebRequest request = (HttpWebRequest)WebRequestCreator.ClientHttp.Create(new Uri(requestUriString));
                 request.Method = httpMethod;
 
                 return request;
             }
             catch (Exception ex)
             {
                 return null;
             }
         }
         #region 上传
 
         private void ReadFileToRequestStream(BinaryReader fileStream, HttpWebRequest request)
         {
             try
             {
                 request.BeginGetRequestStream((requestAsyncResult) =>
                 {
                     Stream requestStream = null;
                     try
                     {
                         requestStream = request.EndGetRequestStream(requestAsyncResult);
                         if (null != requestStream)
                         {
                             SilverlightMultipartFormData form = new SilverlightMultipartFormData();
                             //form.AddFormField("devilField", "中国人");
                             int maxBufferLen = 25 * 1024;
                             byte[] buffer = new byte[maxBufferLen];
                             int bytesRead = fileStream.Read(buffer, 0, maxBufferLen);
                             int i = 0;
                             while (bytesRead != 0)
                             {
                                 i++;
                                 byte[] newBuffer = GetNewBuffer(buffer, bytesRead);
                                 form.AddStreamFile("package" + i, "package" + i, newBuffer);
                                 buffer = new byte[maxBufferLen];
                                 bytesRead = fileStream.Read(buffer, 0, maxBufferLen);
                             }
 
                             form.PrepareFormData();//结束
                             fileStream.Close();
                             request.ContentType = "multipart/form-data; boundary=" + form.Boundary;
                             foreach (byte byt in form.GetFormData())
                             {
                                 requestStream.WriteByte(byt);
                             }
                             requestStream.Close();
                             autoEvent.Set();//开始上传
                         }
                     }
                     catch (Exception ex)
                     { }
                     finally
                     {
                         if (null != requestStream)
                             requestStream.Close();
                         if (null != fileStream)
                             fileStream.Close();
                     }
                 }, null);
             }
             catch (Exception ex)
             {
 
             }
         }
 
         private void RequestAndUploadFile(BinaryReader br)
         {
             try
             {
                 if (null == br) return;
                 HttpWebRequest request = CreateWebRequest("http://localhost:13953/Upload.ashx", "POST");
                 ReadFileToRequestStream(br, request);
                 autoEvent.WaitOne();//等待流写入完毕
 
                 //上传
                 request.BeginGetResponse(
                             (asyncResult) =>
                             {
                                 if (request.HaveResponse)
                                 {
                                     try
                                     {
                                         WebResponse response = request.EndGetResponse(asyncResult);
 
                                         Stream responseStream = response.GetResponseStream();
                                         int bufferLen = 1024;
                                         byte[] buffer = new byte[bufferLen];
                                         int bytesRead = responseStream.Read(buffer, 0, bufferLen);
                                         responseStream.Close();
 
                                         string responseText = System.Text.Encoding.UTF8.GetString(buffer, 0, bytesRead);
 
                                         ShowUploadResult(true);
                                     }
                                     catch (Exception ex)
                                     {
                                         ShowUploadResult(false);
                                     }
                                 }
                             }, null);
             }
             catch (Exception ex)
             {
                 ShowUploadResult(false);
             }
         }
 
         private void btnUpload_Click(object sender, RoutedEventArgs e)
         {
             ofd = new OpenFileDialog();
             ofd.Filter = "(*.rar)|*.rar";
             ofd.Multiselect = false;
 
             if (ofd.ShowDialog() == true)
             {
                 uploadProgress.Visibility = Visibility.Visible;
                 BinaryReader br = new BinaryReader(ofd.File.OpenRead());
                 RequestAndUploadFile(br);
             }
         }
 
         private void ShowUploadResult(bool isSucess)
         {
             this.Dispatcher.BeginInvoke(
                 () =>
                 {
                     uploadProgress.Visibility = Visibility.Collapsed;
                     if (isSucess)
                         MessageBox.Show("上传成功");
                     else
                         MessageBox.Show("上传失败.");
                 });
         }
         #endregion
 
         ///


         /// 获了实际接读取到的字节数组
         ///
         ///
         ///
         ///
         private byte[] GetNewBuffer(byte[] buffer, int bytesRead)
         {
             byte[] newBuffer = new byte[bytesRead];
             for (int i = 0; i < bytesRead; i++)
             {
                 newBuffer[i] = buffer[i];
             }
             return newBuffer;
         }
     }
 }

Upload.ashx文件源码:

 代码如下 复制代码

View Code
 namespace SilverlightDownAndUploadFile.Web
 {
     ///


     /// Upload 的摘要说明
     ///
     public class Upload : IHttpHandler
     {
 
         public void ProcessRequest(HttpContext context)
         {
             //context.Response.ContentType = "text/plain";
             //context.Response.Write("Hello World");
             Stream stream = null;
             try
             {
                 string path = context.Server.MapPath("~/Files/upload.rar");
                 int i = 0;
                 while (true)
                 {
                     i++;
                     string packageName = "package" + i;
                     HttpPostedFile uploadFile = context.Request.Files[packageName];
                     if (null != uploadFile)
                     {
                         stream = context.Request.Files[packageName].InputStream;
                         FileStream fs = null;
                         if (i == 1 && File.Exists(path))
                         {
                             fs = new FileStream(path, FileMode.Create, FileAccess.Write);
                         }
                         else
                         {
                             fs = new FileStream(path, FileMode.Append, FileAccess.Write);
                         }
 
                         using (BinaryWriter bw = new BinaryWriter(fs))
                         {
                             int maxBufferLen = 20 * 1024;//20K
                             byte[] buffer = new byte[maxBufferLen];
                             int bytesRead = stream.Read(buffer, 0, maxBufferLen);
                             while (bytesRead != 0)
                             {
                                 byte[] newBuff = GetNewBuffer(buffer, bytesRead);
                                 bw.Write(newBuff, 0, newBuff.Length);
 
                                 buffer = new byte[maxBufferLen];
                                 bytesRead = stream.Read(buffer, 0, maxBufferLen);
                             }
 
                             //返回本次上传字节数
                             context.Response.Write(stream.Length);
                             context.Response.Flush();
                         }
 
                         stream.Close();
                         fs.Close();
                     }
                     else
                     {
                         if (i != 1)
                             break;
                         else
                             i = 0;
                     }
                 }
 
                 context.Response.Write("Upload Success!");
                 context.Response.Flush();
                 context.Response.End();
             }
             catch (Exception ex)
             {
             }
             finally
             {
                 if (null != stream)
                     stream.Close();
             }
         }
 
         ///
         /// 获取实际读取到的字节数组
         /// <

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