Silverlight文件上傳下載實現方法(下載保存)

2019-10-29 21:36:24

字體：大中小

來源：轉載

供稿：網友

這篇文章主要介紹了Silverlight文件上傳下載實現方法(下載保存) ,需要的朋友可以參考下

search了非常多的文章，總算勉強實現了。有許多不完善的地方。

在HCLoad.Web項目下新建目錄Pics復制一張圖片到根目錄下。

圖片名：Bubble.jpg 右擊->屬性->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="下載保存" NavigateUri="http://localhost:4528/download.ashx?fileName=aa.txt" TargetName="_self" x:Name="lBtnDown" />

<TextBlock x:Name="tbMsgString" Text="下載進度" 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; //因為要使用BitmapImage

using System.IO; //因為要使用Stream

namespace HCLoad

{

public partial class UC_UpDown : UserControl

{

//1、WebClient 對象一次只能啟動一個請求。如果在一個請求完成（包括出錯和取消）前，即IsBusy為true時，進行第二個請求，則第二個請求將會拋出 NotSupportedException 類型的異常

//2、如果 WebClient 對象的 BaseAddress 屬性不為空，則 BaseAddress 與 URI（相對地址）組合在一起構成絕對 URI

//3、WebClient 類的 AllowReadStreamBuffering 屬性：是否對從 Internet 資源接收的數據做緩沖處理。默認值為true，將數據緩存在客戶端內存中，以便隨時被應用程序讀取

//獲取選定圖片信息

System.IO.FileInfo fileinfo;

public UC_UpDown()

{

InitializeComponent();

}

#region 下載圖片

private void btnDownload_Click(object sender, RoutedEventArgs e)

{

//向指定的Url發送下載流數據請求

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 - 該異步操作期間是否發生了錯誤

//OpenReadCompletedEventArgs.Cancelled - 該異步操作是否已被取消

//OpenReadCompletedEventArgs.Result - 下載后的 Stream 類型的數據

//OpenReadCompletedEventArgs.UserState - 用戶標識

if (e.Error != null)

{

MessageBox.Show(e.Error.ToString());

return;

}

if (e.Cancelled != true)

{

//獲取下載的流數據(在此處是圖片數據)并顯示在圖片控件中

//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 - 下載完成的百分比

//DownloadProgressChangedEventArgs.BytesReceived - 當前收到的字節數

//DownloadProgressChangedEventArgs.TotalBytesToReceive - 總共需要下載的字節數

//DownloadProgressChangedEventArgs.UserState - 用戶標識

this.tbMsgString.Text = string.Format("完成百分比：{0} 當前收到的字節數：{1} 資料大小：{2} ",

e.ProgressPercentage.ToString() + "%",

e.BytesReceived.ToString(),

e.TotalBytesToReceive.ToString());

}

#endregion

#region 上傳圖片

private void btnUpLoad_Click(object sender, RoutedEventArgs e)

{

/**/

/*

*　　 OpenWriteCompleted - 在打開用于上傳的流完成時（包括取消操作及有錯誤發生時）所觸發的事件

*　　 WriteStreamClosed - 在寫入數據流的異步操作完成時（包括取消操作及有錯誤發生時）所觸發的事件

*　　 UploadProgressChanged - 上傳數據過程中所觸發的事件。如果調用 OpenWriteAsync() 則不會觸發此事件

*　　 Headers - 與請求相關的的標頭的 key/value 對**

*　　 OpenWriteAsync(Uri address, string method, Object userToken) - 打開流以使用指定的方法向指定的 URI 寫入數據

*　　　　 Uri address - 接收上傳數據的 URI

*　　　　 string method - 所使用的 HTTP 方法（POST 或 GET）

*　　　　 Object userToken - 需要上傳的數據流

*/

OpenFileDialog openFileDialog = new OpenFileDialog()

{ //彈出打開文件對話框要求用戶自己選擇在本地端打開的圖片文件

Filter = "Jpeg Files (*.jpg)|*.jpg|All Files(*.*)|*.*",

Multiselect = false //不允許多選

};

if (openFileDialog.ShowDialog() == true)//.DialogResult.OK)

{

//fileinfo = openFileDialog.Files; //取得所選擇的文件，其中Name為文件名字段，作為綁定字段顯示在前端

fileinfo = openFileDialog.File;

if (fileinfo != null)

{

WebClient webclient = new WebClient();

string uploadFileName = fileinfo.Name.ToString(); //獲取所選文件的名字

#region 把圖片上傳到服務器上

Uri upTargetUri = new Uri(String.Format("http://localhost:4528/WebClientUpLoadStreamHandler.ashx?fileName={0}", uploadFileName), UriKind.Absolute); //指定上傳地址

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("請選取想要上載的圖片!!!");

}

}

}

void webclient_OpenWriteCompleted(object sender, OpenWriteCompletedEventArgs e)

{

//將圖片數據流發送到服務器上

// e.UserState - 需要上傳的流（客戶端流）

Stream clientStream = e.UserState as Stream;

// e.Result - 目標地址的流（服務端流）

Stream serverStream = e.Result;

byte[] buffer = new byte[4096];

int readcount = 0;

// clientStream.Read - 將需要上傳的流讀取到指定的字節數組中

while ((readcount = clientStream.Read(buffer, 0, buffer.Length)) > 0)

{

// serverStream.Write - 將指定的字節數組寫入到目標地址的流

serverStream.Write(buffer, 0, readcount);

}

serverStream.Close();

clientStream.Close();

}

void webclient_WriteStreamClosed(object sender, WriteStreamClosedEventArgs e)

{

//判斷寫入是否有異常

if (e.Error != null)

{

System.Windows.Browser.HtmlPage.Window.Alert(e.Error.Message.ToString());

}

else

{

System.Windows.Browser.HtmlPage.Window.Alert("圖片上傳成功!!!");

}

}

#endregion

private void Button_Click(object sender, RoutedEventArgs e)

{

//這種方法搞不定，好像提示跨域操作。

//提示：錯誤：Unhandled Error in Silverlight Application 跨線程訪問無效。

//Uri upTargetUri = new Uri(String.Format("http://localhost:4528/download.ashx?filename={0}", "123.jpg"), UriKind.Absolute); //指定上傳地址

//WebRequest request = WebRequest.Create(upTargetUri);

//request.Method = "GET";

//request.ContentType = "application/octet-stream";

//request.BeginGetResponse(new AsyncCallback(RequestReady), request);

//通過調用js代碼下載，比較簡單。

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項目下新建WebClientUpLoadStreamHandler.ashx

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.IO; //因為要用到Stream

namespace HCLoad.Web

{

public class WebClientUpLoadStreamHandler : IHttpHandler

{

public void ProcessRequest(HttpContext context)

{

//獲取上傳的數據流

string fileNameStr = context.Request.QueryString["fileName"];

Stream sr = context.Request.InputStream;

try

{

string filename = "";

filename = fileNameStr;

byte[] buffer = new byte[4096];

int bytesRead = 0;

//將當前數據流寫入服務器端文件夾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)

{

//向文件中寫信息

fs.Write(buffer, 0, bytesRead);

}

}

context.Response.ContentType = "text/plain";

context.Response.Write("上傳成功");

}

catch (Exception e)

{

context.Response.ContentType = "text/plain";

context.Response.Write("上傳失敗, 錯誤信息:" + 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>

/// $codebehindclassname$ 的摘要說明

/// </summary>

public class download : IHttpHandler

{

private long ChunkSize = 102400;//100K 每次讀取文件，只讀取100Ｋ，這樣可以緩解服務器的壓力

public void ProcessRequest(HttpContext context)

{

//string fileName = "123.jpg";//客戶端保存的文件名

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;//獲得下載文件的總大小

context.Response.ContentType = "application/octet-stream";

//通知瀏覽器下載文件而不是打開

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));//讀取的大小

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;

}

}

}

}