摘要：
文件上传是日常开过程中最常用的功能之一，目前实现文件上传的方式多种多样。这其中较为复杂的情况就是关于大文件、多文件上传的问题，目前解决大文件、多文件上传一般借助于js或者flash组件，今天就同大家一起看一下如何使用silverlight实现这个功能，而且功能和用户体验相对会更好一些。
主要内容：
一、组件特点
二、实现原理
三、编码实现
一、组件特点
对于今天要说的组件姑且叫做"CmjUpload"吧，方便称呼。目前有很多上传组件来辅助完成日常开发，"CmjUpload"有什么特点呢：
- 解决大文件、多文件上传问题
- 基于asp.net上传，不需要部署WCF、WebService操作方便
- 接口丰富、灵活性强，配置使用方便。
- 支持选择、拖拽两种文件添加方式上传，用户体验好。
- 支持取消、暂停、继续操作满足续传要求。
OK，就说那么多吧，主要是让大家有兴趣看下去，其实之所以有今天的话题主要还是为了学习以及满足实际开发需求。
二、实现原理
在Silverlight中要实现上传有很多方式，例如说使用WCF或者WebService，但是考虑到实际情况，这里没有选择以上两种方式，而是选择了WebRequest方式。原因比较简单，部署十分方便，不需要为了上传组件而进行额外的配置。Silverlight中使用WebRequest同其他.Net开发中的使用方式是类似的，不同的是Silverlight中很多操作都是异步的，当然WebRequest也不例外。此外，在这里需要对一个文件分块发送，一方面可以解决大文件上传问题，另一方面可以实时显示文件上传进度。下面一个简单的交互过程：
当然要完成整个组件远不止上面说的这些，UI的设计，组件的本地化，用户接口的设计等都是必须思考的问题。下面是组件界面原型：
界面分为两个区域：文件显示区域和操作区域，当然这里的文件区域本身也是可以操作的，例如如果你不想点击按钮选择文件的话，可以选择直接拖拽一个或多个文件到文件区域。还可以对已添加的文件进行删除操作，对正在上传的文件进行暂停和续传操作。此外文件区域的设计主要提供文件信息显示，例如缩略图、上传进度、文件名称、文件大小等信息。操作区域一方面提供文件整体信息的显示（例如文件总数、已上传数等），另一方面提供了文件浏览、上传、清空操作。
下面是类的设计：
在上图中我们可以看出有三个包：Core、Config、Util。
Core是核心包，里面主要包括文件队列管理（FileQueue）、文件上传控制（FileUpload）、文件界面区域（FileArea）、文件大小单位转换（FileSize）、缩略图控制（FileIcon）。
Config是配置和接口包，主要包括组件设计级别常量（注意不是用户级别也不是开发级别，开发级别配置在接口中进行）（UploadConstant）、客户端开发接口（ExposeInterface）、本地化实现（Localization）、接口注册（ClientInteraction）。
Util包主要包括一些常用辅助类，主要包括xml操作（XmlHelper）、服务器端文件保存辅助类（CmjUpload）。
三、编码实现
有了上面的分析相信下面的实现就相当容易理解了，首先看一下文件上传类FileUpload：
using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Text;
using System.IO;
using System.Windows.Threading;
using CmjUpload.Util;
using CmjUpload.Config;
namespace CmjUpload
{
public class FileUpload
{
//开始上传
public delegate void StartUploadHanler(object sender,EventArgs e);
public event StartUploadHanler StartUpload;
public void OnStartUpload(object sender, EventArgs e)
{
if (StartUpload != null)
{
StartUpload(sender, e);
}
}
// 上传
public delegate void UploadingHanler(object sender, ProgressArgs e);
public event UploadingHanler Uploading;
public void OnUploading(object sender, ProgressArgs e)
{
if (Uploading != null)
{
Uploading(sender,e);
}
}
//上传结束
public delegate void UploadCompletedHanler(object sender, EventArgs e);
public event UploadCompletedHanler UploadCompleted;
public void OnUploadCompleted(object sender, EventArgs e)
{
if (UploadCompleted != null)
{
UploadCompleted(sender, e);
}
}
private string _requestUrl = "";
private string _fileName = "";
private long _fileLength = 0;
private long _blockLength = 4096;//单次上传文件大小
private long _postedLength = 0;//已传输文件大小
private long _nextLength = 0;//下次传输的文件大小
private bool _firstUpload = true;
private BinaryReader _fileReader = null;
private UploadStatus _uploadStatus = UploadStatus.Start;
public FileInfo File
{
get;
set;
}
//public long PostedLength
//{
// get
// {
// return _postedLength;
// }
// set
// {
// _postedLength = value;
// }
//}
public UploadStatus Status
{
get
{
return _uploadStatus;
}
set
{
_uploadStatus = value;
}
}
public void Upload(FileInfo file)
{
this.File = file;
//XmlHelper xmlHelper = new XmlHelper("Config/CmjUploadConfig.xml");
//_requestUrl=xmlHelper.GetAttibuteValue("Upload", "RequestUrl");
_requestUrl = ExposeInterface.Instance().RequestUrl;
this._fileName = this.File.Name;
this._fileLength = this.File.Length;
this._blockLength = FileSize.GetLockSize(this._fileLength);
//this._postedLength = 0;
_fileReader = new BinaryReader(file.OpenRead());
//_uploadStatus = UploadStatus.Start;
if (_fileLength < _blockLength)
{
_nextLength = _fileLength;
}
else
{
_nextLength = _blockLength;
}
OnStartUpload(this, new EventArgs());
UploadInBlock();
}
public void UploadInBlock()//上传一块数据
{
UriBuilder uriBuilder = new UriBuilder(new Uri(_requestUrl, UriKind.Absolute));
uriBuilder.Query = string.Format("fileName={0}&status="+_uploadStatus,this._fileName);
WebRequest request = WebRequest.Create(uriBuilder.Uri);
request.Method = "POST";
request.ContentType = "multipart/mixed";//注意这里
request.ContentLength = _nextLength;
if (_firstUpload)
{
_uploadStatus = UploadStatus.Uploading;
_firstUpload = false;
}
request.BeginGetRequestStream((IAsyncResult asyncResult) =>
{
WebRequest rqst = asyncResult.AsyncState as WebRequest;
Stream rqstStm = rqst.EndGetRequestStream(asyncResult);
byte[] buffer = new byte[_blockLength];
int size = _fileReader.Read(buffer, 0, buffer.Length);
if(size>0)
{
rqstStm.Write(buffer, 0, size);
rqstStm.Flush();
_postedLength += size;
if ((_fileLength - _postedLength) < _blockLength)
{
_nextLength = _fileLength-_postedLength;
}
}
rqstStm.Close();
rqst.BeginGetResponse((IAsyncResult ascResult) =>//开始数据传输
{
OnUploading(this, new ProgressArgs() { Percent = ((double)_postedLength / (double)_fileLength) });
WebRequest webRequest = ascResult.AsyncState as WebRequest;
WebResponse webResponse = (WebResponse)webRequest.EndGetResponse(ascResult);
StreamReader reader = new StreamReader(webResponse.GetResponseStream());
string responsestring = reader.ReadToEnd();
reader.Close();
if (_postedLength >= _fileLength)
{
_uploadStatus = UploadStatus.Complelte;
}
if (_uploadStatus == UploadStatus.Uploading)
{
UploadInBlock();
}
//else if(_uploadStatus==UploadStatus.Cancel)
//{
// return;
//}
else if (_uploadStatus==UploadStatus.Complelte)
{
_fileReader.Close();
OnUploadCompleted(this, new EventArgs());
}
}, request);
}, request);
}
/// <summary>
/// 继续上传
/// </summary>
/// <param name="fileName"></param>
/// <param name="uploadedLength"></param>
//public static void ContinueUplaod(string fileName,long uploadedLength)
//{
//}
}
//上传进度参数
public class ProgressArgs:EventArgs
{
public double Percent
{
get;
set;
}
}
public enum UploadStatus
{
Start,
Uploading,
Cancel,
Complelte
}
}
在这个类中需要注意的是状态的控制，因为组件需要实现文件暂停、续传功能，并且每次请求时需要发送相应的操作状态；另一点就是对外公开了三个事件，用于给UI提供进度支持和状态通知。
FileQueue管理整个文件队列，控制着界面UI、文件上传等信息：
using System;
using System.Collections.Generic;
using System.IO;
namespace CmjUpload
{
/// <summary>
/// 文件队列管理者
/// </summary>
public class FileQueue
{
private static object _lock = new object();
private static FileQueue _fileQueue = null;
private Dictionary<string, int> _fileIndexs = null;//文件同索引对应关系
private Dictionary<string,FileInfo> _files = null;
private Dictionary<string,FileArea> _fileAeas = null;
private Dictionary<string, FileUpload> _fileUploader = null;
private int index = 0;
private FileQueue()
{
_fileIndexs = new Dictionary<string, int>();
_files = new Dictionary<string, FileInfo>();
_fileAeas = new Dictionary<string, FileArea>();
_fileUploader = new Dictionary<string, FileUpload>();
}
public static FileQueue Instance()
{
lock (_lock)
{
if (_fileQueue == null)
{
_fileQueue = new FileQueue();
}
}
return _fileQueue;
}
public void Add(FileInfo file)
{
_fileIndexs.Add(file.Name, index);
_files.Add(file.Name,file);
FileArea fileAerea = new FileArea(file);
_fileAeas.Add(file.Name, fileAerea);
++index;
}
public void Remove(string fileName)
{
_fileIndexs.Remove(fileName);
_files.Remove(fileName);
_fileAeas.Remove(fileName);
_fileUploader.Remove(fileName);
}
public Dictionary<string,FileInfo> Files
{
get
{
return _files;
}
set
{
_files = value;
}
}
public Dictionary<string, FileArea> FileAreas
{
get
{
return _fileAeas;
}
set
{
_fileAeas = value;
}
}
public Dictionary<string, FileUpload> FileUploader
{
get
{
return _fileUploader;
}
set
{
_fileUploader = value;
}
}
public int GetFileIndex(string fileName)
{
int i=-1;
if (_fileIndexs.ContainsKey(fileName))
{
i = _fileIndexs[fileName];
}
return i;
}
public void Clear()
{
string[] tempFileNames=new string[this.Files.Count];
this.Files.Keys.CopyTo(tempFileNames,0);
foreach (string fileName in tempFileNames)
{
this.Remove(fileName);
}
}
}
}
FileArea用于构建每个文件的UI展示：
using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Windows.Media.Imaging;
using System.IO;
using Cmj.MyWeb.MySilverlight.MyUserControl.Button;
namespace CmjUpload
{
public class FileArea
{
private FileInfo _file = null;
//private int _number = 0;
private Grid _container = null;
private TextBlock _name = null;
private Image _thumnail = null;
private ProgressBar _progress = null;
private TextBlock _size = null;
private TextBlock _percent = null;
private Cancel _cancel = null;
private Pause _pause = null;
private Play _continue = null;
private Check _complete = null;
public FileArea(FileInfo file)
{
_file = file;
//_number = number;
_container = new Grid();
_container.Name = "fileArea_container_" + file.Name;
_container.ColumnDefinitions.Add(new ColumnDefinition() { Width = new GridLength(60)});
_container.ColumnDefinitions.Add(new ColumnDefinition());
_container.ColumnDefinitions.Add(new ColumnDefinition() { Width=new GridLength(60)});
_container.ColumnDefinitions.Add(new ColumnDefinition() { Width = new GridLength(60) });
_container.Height = 50;
_thumnail = new Image();
_thumnail.Name = "fileArea_thumnail_" + file.Name;
_thumnail.Height = 40;
_thumnail.Source = FileIcon.Instance().GetThumbnailImage(file);
_thumnail.VerticalAlignment = VerticalAlignment.Bottom;
_thumnail.HorizontalAlignment = HorizontalAlignment.Center;
Grid.SetColumn(_thumnail, 0);
_progress = new ProgressBar();
_progress.Name = "fileArea_progress_" + file.Name;
_progress.Minimum = 0;
_progress.Maximum = 100;
_progress.Value = 0;
_progress.Height = 20;
_progress.VerticalAlignment = VerticalAlignment.Bottom;
//_progress.HorizontalAlignment = HorizontalAlignment.Center;
Grid.SetColumn(_progress, 1);
_name = new TextBlock();
_name.Name = "fileArea_name_" + file.Name;
_name.Text = file.Name;
_name.VerticalAlignment = VerticalAlignment.Bottom;
_name.HorizontalAlignment = HorizontalAlignment.Left;
_name.Margin = new Thickness(10, 0, 0, 2);
Grid.SetColumn(_name, 1);
_percent = new TextBlock();
_percent.Name = "fileArea_percent_" + file.Name;
_percent.VerticalAlignment = VerticalAlignment.Bottom;
_percent.HorizontalAlignment = HorizontalAlignment.Right;
_percent.Margin = new Thickness(0, 0, 10, 2);
Grid.SetColumn(_percent, 1);
_size = new TextBlock();
_size.Name = "fileArea_size_" + file.Name;
_size.VerticalAlignment = VerticalAlignment.Bottom;
_size.HorizontalAlignment = HorizontalAlignment.Right;
Grid.SetColumn(_size, 2);
_cancel = new Cancel();
_cancel.Name = "fileArea_cancel_"+file.Name;
_cancel.Width = 15;
_cancel.Height = 15;
_cancel.VerticalAlignment = VerticalAlignment.Bottom;
//_cancel.Click += new RoutedEventHandler(_cancel_Click);
Grid.SetColumn(_cancel, 3);
_pause = new Pause();
_pause.Name = "fileArea_pause_" + file.Name;
_pause.Width = 15;
_pause.Height = 15;
_pause.VerticalAlignment = VerticalAlignment.Bottom;
_pause.Visibility = Visibility.Collapsed;
Grid.SetColumn(_pause, 3);
_continue = new Play();
_continue.Name = "fileArea_continue_" + file.Name;
_continue.Width = 15;
_continue.Height = 15;
_continue.VerticalAlignment = VerticalAlignment.Bottom;
_continue.Visibility = Visibility.Collapsed;
Grid.SetColumn(_continue, 3);
_complete = new Check();
_complete.Name = "fileArea_complete_" + file.Name;
_complete.Width = 18;
_complete.Height = 18;
_complete.VerticalAlignment = VerticalAlignment.Bottom;
_complete.Visibility = Visibility.Collapsed;
Grid.SetColumn(_complete, 3);
_container.Children.Add(_thumnail);
_container.Children.Add(_progress);
_container.Children.Add(_size);
_container.Children.Add(_name);
_container.Children.Add(_percent);
_container.Children.Add(_cancel);
_container.Children.Add(_pause);
_container.Children.Add(_continue);
_container.Children.Add(_complete);
}
public Grid Container
{
get
{
return _container;
}
set
{
_container = value;
}
}
public TextBlock Name
{
get
{
return _name;
}
set
{
_name = value;
}
}
public Image Thumnail
{
get
{
return _thumnail;
}
set
{
_thumnail = value;
}
}
public ProgressBar Progress
{
get
{
return _progress;
}
set
{
_progress = value;
}
}
public TextBlock Size
{
get
{
return _size;
}
set
{
_size = value;
}
}
public TextBlock Percent
{
get
{
return _percent;
}
set
{
_percent = value;
}
}
public Cancel Cancel
{
get
{
return _cancel;
}
set
{
_cancel = value;
}
}
public Pause Pause
{
get
{
return _pause;
}
set
{
_pause = value;
}
}
public Play Continue
{
get
{
return _continue;
}
set
{
_continue = value;
}
}
public Check Complete
{
get
{
return _complete;
}
set
{
_complete = value;
}
}
}
}
ExposeInterface用于向客户端调用提供操作接口：
using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Collections.Generic;
using System.Windows.Browser;
namespace CmjUpload.Config
{
public class ExposeInterface
{
private static object _lock = new object();
private static ExposeInterface _exposeInterface = null;
private string _fileTypes = string.Empty;
private string _fileDialogFilter = string.Empty;
private long _limitSize = 0;
private int _limitCount = 0;
private ExposeInterface()
{
}
public static ExposeInterface Instance()
{
lock (_lock)
{
if (_exposeInterface == null)
{
_exposeInterface = new ExposeInterface();
}
}
return _exposeInterface;
}
[ScriptableMember]
public string FileTypes //ex:*.jpg|*.gif
{
get
{
return _fileTypes;
}
set
{
_fileTypes = value;
}
}
[ScriptableMember]
public string FileDialogFilter
{
get
{
if (this._fileDialogFilter == string.Empty&&this._fileTypes!=string.Empty)
{
string[] types = this._fileTypes.Split('|');
string[] filters=new string[types.Length];
for(int i=0;i<types.Length;++i)
{
filters[i] = "("+types[i] +")|"+ types[i];
}
_fileDialogFilter = string.Join("|",filters);
}
return _fileDialogFilter;
}
set
{
_fileDialogFilter = value;
}
}
[ScriptableMember]
public long LimitSize//单位 MB
{
get
{
return _limitSize;
}
set
{
_limitSize = value;
}
}
[ScriptableMember]
public int LimitCount
{
get
{
return _limitCount;
}
set
{
_limitCount = value;
}
}
[ScriptableMember]
public string RequestUrl
{
get;
set;
}
public List<string> GetFileExtensions()
{
List<string> extensions = new List<string>();
string[] types = this._fileTypes.Split(new char[] { '|' }, StringSplitOptions.RemoveEmptyEntries);
foreach(string type in types)
{
extensions.Add(type.TrimStart('*'));
}
return extensions;
}
}
}
CmjUpload用于提供给服务器端进行文件操作，服务端只需要简单调用其Save方法就可以进行文件保存：
using System;
using System.Collections.Generic;
using System.Web;
using System.IO;
namespace CmjUpload.Web.Util
{
public class CmjUpload
{
public static void Save(string relationPath)
{
string fileName = HttpContext.Current.Request["fileName"];
Save(relationPath,fileName);
}
public static void Save(string relationPath,string outputName)
{
string status = HttpContext.Current.Request["status"];
if (status == "Start")
{
using (FileStream fs = File.Create(Path.Combine(relationPath, outputName)))
{
SaveFile(HttpContext.Current.Request.InputStream, fs);
}
}
else if (status == "Uploading")
{
using (FileStream fs = File.Open(Path.Combine(relationPath, outputName), FileMode.Append))
{
SaveFile(HttpContext.Current.Request.InputStream, fs);
}
}
else if (status == "Completed")
{
HttpContext.Current.Response.Write("{success:true}");
}
}
private static void SaveFile(Stream stream, FileStream fs)
{
byte[] buffer = new byte[4096];
int bytesRead;
while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) != 0)
{
fs.Write(buffer, 0, bytesRead);
}
}
}
}
OK，其他的代码就不再贴出了，看一下客户端如何使用吧。
为了方便使用客户端提供一个公用js类CmjUpload.js：
//注意要在控件加载完之后调用,建议放到插件onload事件中初始化（<param name="onLoad" value="pluginLoaded" />）
var CmjUpload = function (options) {
var uploader = null;
if (options.hasOwnProperty("id")) {//组件id
uploader = document.getElementById(options.id);
} else {
alert("Please configure the id attribute before use CmjUpload component！");
return;
}
if (options.hasOwnProperty("requestUrl")) {//请求的url
uploader.content.cmjUpload.RequestUrl = options.requestUrl;
} else {
alert("Please configure the requestUrl attribute before use CmjUpload component！");
return;
}
if (options.hasOwnProperty("fileTypes")) {//文件类型限制
uploader.content.cmjUpload.FileTypes = options.fileTypes;
}
if (options.hasOwnProperty("limitCount")) {//每批次上传的文件数
uploader.content.cmjUpload.LimitCount = options.limitCount;
}
if (options.hasOwnProperty("limitSize")) {//单个文件大小限制
uploader.content.cmjUpload.LimitSize = options.limitSize;
}
}
CmjUpload.prototype.onBeforeFileUpload = function () {//单个文件上传之前执行
}
CmjUpload.prototype.onFileUploading = function () { //单个文件上传时执行
}
CmjUpload.prototype.onFileUploaded = function () {//单个文件上传完毕执行
}
CmjUpload.prototype.onBatchUploaded = function () {//整个批次的文件上传完毕执行
}
然后在页面添加上传组件（本地化语言在param中进行配置）：
<object id="cmjUpload1" data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="100%" height="100%">
<param name="source" value="ClientBin/CmjUpload.xap"/>
<param name="onError" value="onSilverlightError" />
<param name="onLoad" value="pluginLoaded" /><!--注意这里，必须保证配置信息在页面加载之后执行-->
<param name="culture" value="en-US" /><!--注意这里本地化配置-->
<param name="uiculture" value="en-US" /><!--注意这里本地化配置-->
<param name="background" value="white" />
<param name="minRuntimeVersion" value="4.0.50826.0" />
<param name="autoUpgrade" value="true" />
<a href="http://go.microsoft.com/fwlink/?LinkID=149156&v=4.0.50826.0" style="text-decoration:none">
<img src="http://go.microsoft.com/fwlink/?LinkId=161376" alt="Get Microsoft Silverlight" style="border-style:none"/>
</a>
</object>
使用时在页面引用该类，进行id和url等信息配置，具体的配置内容上面js已经注释的很清楚，这里不再赘余。例如对页面做如下配置：
pluginLoaded=function(){
var upload = new CmjUpload({ id: 'cmjUpload1', requestUrl: 'http://localhost:3407/Upload.aspx', fileTypes: '*.jpg|*.png|*.wmv|*.rar|*.iso', limitCount: 5, limitSize: 150 });
}
后台文件执行文件保存操作：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
namespace CmjUpload.Web
{
public partial class Upload : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
CmjUpload.Web.Util.CmjUpload.Save("f:\\");
}
}
}
下面是使用效果：
类型限制
大小限制
数量限制
删除一个文件
上传中
上传暂停
完成上传
手动清空（即使不手动清空继续上传文件会自动清空，清空操作主要用于上传暂停后不需要上传的清空）
下面看看本地化设置为英文后的效果
我们通过修改LimitCount来看一下大文件传输，好几个G的文件同时传输也没有问题
OK，最后附上组件下载，使用方法上面说的也比较清楚了。关于组件源代码就不再提供下载了，相信读完这篇文章要实现并不难，真正需要的话可以给我留言或发邮件KenshinCui@hotmail.com。
组件下载
