积极的人在每一次忧患中都看到一个机会，而消极的人则在每个机会都看到某种忧患。
最近做项目中遇到很多问题，比如带进度条的文件上传，看了网上很多资料还没找到真正意义上的ASP.NET实现进度条上传（可能是我没找到），下面我来跟大家分享一下我实现的这个程序。
首先看下界面效果，当然你可以完全修改界面为你自己所用。
先解释一下这个程序，该程序采用了jquery框架，实现了小文件上传，不超过80Mb，可以在web.config文件中进行相应的配置，但是有个最大值，具体需要查看msdn。开发环境采用visual studio 2013 .net framework 4.5，运行的时候大家注意一下是否满足要求，好了，下面直入正题。
先来看看实现原理。基本原理：一个页面进行文件上传，另外一个页面去监听这个文件上传了多少。
这里面有两个地方需要解释一下：第一个，如何知道监听的这个文件就是上传的这个文件？实现机制很简单，就是让asp.net产生一个唯一的guid，这个id序号是唯一的，通过ajax取出来赋值给一个隐藏字段；第二个，如何获取guid标志的文件信息？通过asp.net缓存机制实现，上传的过程中，不断的将上传信息往缓存里面写，直到文件上传完成，而在另外一个通过guid获取缓存的信息，信息包括你想要的信息，比如上传了多少字节、消耗了多长时间等。好了，要点就解释到这里，有疑问的话给我留言。
下面来说说具体的实现：
文件目录结构如下：
index.htm就是文件上传页面，提交form给UploadHandler目录下的Default.aspx，以实现文件上传。
ProgressHandler目录下三个文件为Abort.ashx、GenericGuid.ashx,Handler.ashx功能分别为：根据Guid取消正在上传的文件，生成Guid，根据Guid获取上传信息。
第一步：建立index.htm页面，这个上传页面，需要注意的就是需要一个隐藏的iframe，并且名字为form提交的目标。
<!DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>ASP.NET Ajax文件上传进度条示例</title>
<meta name="author" content="李检全" />
<link rel="nofollow noopener noreferrer" href="Styles/base.css" rel="stylesheet" type="text/css" />
<script src="Scripts/jquery-1.4.2.min.js" type="text/javascript"></script>
<script src="Scripts/jquery-ui-1.8.2.custom.min.js" type="text/javascript"></script>
<script src="Scripts/ljq.lib.js" type="text/javascript"></script>
<script src="Scripts/Ajax/GuidGet.js" type="text/javascript"></script>
<script src="Scripts/Ajax/ajax-progress-upload.js" type="text/javascript"></script>
</head>
<body>
<div id="upload_demo">
<div class="title">ASP.NET Ajax 文件上传进度条示例</div>
<form action="UploadHandler/Default.aspx" enctype="multipart/form-data" method="post" target="upload_hidden_iframe">
<input id="guid" name="guid" value="" type="hidden" />
<p>*本程序适合小文件上传，不超过80Mb</p>
<p>文件地址</p>
<input name="upload_file" type="file" />
<br />
<p>文件描述</p>
<textarea name="description_file"></textarea>
<br />
<br />
<input type="submit" value="上传文件" />
</form>
</div>
<div id="back_panel"></div>
<div id="upload_panel">
<div id="upload_title">文件上传</div>
<div id="upload_content">
<ul>
<li id="finished_percent">正在准备上传...</li>
<li><div id="upload_bar"><div id="upload_progress"></div></div></li>
<li id="upload_speed"></li>
<li id="upload_costTime"></li>
<li id="upload_fileSize"></li>
<li id="upload_fileName"></li>
</ul>
<div id="upload_detail"></div>
<div id="upload_choose">
<span id="upload_cancel">取消</span><span id="upload_submit">确定</span>
</div>
</div>
</div>
<iframe name="upload_hidden_iframe" style="display:none;"></iframe>
</body>
</html>
第二步，创建GenerateGuid.ashx文件，作用就是生成唯一的Guid。
<%@ WebHandler Language="C#" Class="ProgressHandler.Handler" %>
using System;
using System.Web;
using System.Xml.Linq;
namespace ProgressHandler
{
public class Handler : IHttpHandler
{
/// <summary>
/// 获得上传文件的GUID
/// </summary>
/// <param name="context">当前请求实体</param>
/// <creattime>2015-06-28</creattime>
/// <author>FreshMan</author>
public void ProcessRequest(HttpContext context)
{
context.Response.Charset = "utf-8";
context.Response.ContentType = "application/xml";
var guid = Guid.NewGuid().ToString();
var doc = new XDocument();
var root = new XElement("root");
var xGuid = new XElement("guid", guid);
root.Add(xGuid);
doc.Add(root);
context.Response.Write(doc.ToString());
context.Response.End();
}
public bool IsReusable
{
get { return false; }
}
}
}
第三步，创建Default.aspx文件，用于提交表单时上传文件。
using System;
namespace UploadHandler
{
public partial class UploadHandlerDefault : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
string guid = Request.Params["guid"];
UploadUtil utilHelp = new UploadUtil(this, guid);
utilHelp.Upload();
}
}
}
上传核心代码：
using System;
using System.Web;
using System.IO;
using System.Configuration;
using System.Web.UI;
using System.Web.Caching;
using System.Threading;
public class UploadUtil
{
private Stream _reader;
private FileStream _fStream;
private const int Buffersize = 10000;
private readonly string _filePath =new Page().Server.MapPath(ConfigurationManager.AppSettings["upload_folder"]);
private readonly Page _page;
private readonly string _guid;
public UploadUtil(Page page, string guid)
{
_page = page;
_guid = guid;
}
public void Upload()
{
if (_page.Request.Files.Count > 0)
{
DoUpload(_page.Request.Files[0]);
}
}
private void DoUpload(HttpPostedFile postedFile)
{
bool abort = false;
string uploadFilePath = _filePath + DateTime.Now.ToFileTime()+"//";
if (!Directory.Exists(uploadFilePath))
{
Directory.CreateDirectory(uploadFilePath);
}
string uploadFileName = postedFile.FileName;
DownloadingFileInfo info = new DownloadingFileInfo(uploadFileName, postedFile.ContentLength, postedFile.ContentType);
object fileObj = HttpContext.Current.Cache[_guid];
if (fileObj != null)
{
HttpContext.Current.Cache.Remove(_guid);
}
HttpContext.Current.Cache.Add(_guid, info, null, DateTime.Now.AddDays(1), TimeSpan.Zero, CacheItemPriority.AboveNormal, null);
DateTime begin=DateTime.Now.ToLocalTime();
_fStream = new FileStream(uploadFilePath + uploadFileName, FileMode.Create);
_reader = postedFile.InputStream;
byte []buffer=new byte[Buffersize];
int len = _reader.Read(buffer,0,Buffersize);
while (len > 0&&!abort)
{
_fStream.Write(buffer,0,len);
DateTime end = DateTime.Now.ToLocalTime();
info.CostTime = (long)(end - begin).TotalMilliseconds;
info.FileFinished += len;
//模拟延时用，实际应用的时候注销他
Thread.Sleep(1000);
HttpContext.Current.Cache[_guid] = info;
abort=((DownloadingFileInfo)HttpContext.Current.Cache[_guid]).Abort;
len = _reader.Read(buffer,0,Buffersize);
}
_reader.Close();
_fStream.Close();
if (abort)
{
if (File.Exists(uploadFilePath + uploadFileName))
{
File.Delete(uploadFilePath + uploadFileName);
}
}
}
}
第四步，创建Handler.ashx文件，用于查看文件上传情况。
<%@ WebHandler Language="C#" Class="ProgressHandler.Handler" %>
using System.Web;
using System.Xml.Linq;
namespace ProgressHandler
{
public class Handler : IHttpHandler
{
/// <summary>
/// 获得上传文件的进度
/// </summary>
/// <param name="context">当前请求实体</param>
/// <creattime>2015-06-28</creattime>
/// <author>FreshMan</author>
public void ProcessRequest(HttpContext context)
{
context.Response.ContentType = "application/xml";
context.Response.Charset = "utf-8";
var guid = context.Request.Form["guid"];
var info = context.Cache[guid] as DownloadingFileInfo;
var doc = new XDocument();
var root = new XElement("root");
if (info != null)
{
var fileName = new XElement("fileName", info.FileName);
var fileFinished = new XElement("fileFinished", info.FileFinished);
var fileSize = new XElement("fileSize", info.FileSize);
var costTime = new XElement("costTime", info.CostTime);
var fileState = new XElement("fileState", info.FileState);
var speed = new XElement("speed", info.Speed);
var percent = new XElement("percent", info.Percent);
var abort = new XElement("abort", false);
root.Add(fileName);
root.Add(fileFinished);
root.Add(fileSize);
root.Add(costTime);
root.Add(fileState);
root.Add(speed);
root.Add(percent);
if (info.Abort)
{
abort.Value = info.Abort.ToString();
context.Cache.Remove(guid);
}
if (info.FileState == "finished")
{
context.Cache.Remove(guid);
}
}
else
{
var none = new XElement("none", "no file");
root.Add(none);
}
doc.Add(root);
context.Response.Write(doc.ToString());
context.Response.End();
}
public bool IsReusable
{
get { return false; }
}
}
}
第五步，创建Abort.ashx文件，用于取消上传。
<%@ WebHandler Language="C#" Class="ProgressHandler.Abort" %>
using System.Web;
using System.Xml.Linq;
namespace ProgressHandler
{
public class Abort : IHttpHandler
{
/// <summary>
/// 取消上传处理程序
/// </summary>
/// <param name="context">当前请求实体</param>
/// <creattime>2015-06-28</creattime>
/// <author>FreshMan</author>
public void ProcessRequest(HttpContext context)
{
context.Response.ContentType = "application/xml";
context.Response.Charset = "utf-8";
var guid = context.Request.Form["guid"];
var abort = !string.IsNullOrEmpty(context.Request.Form["abort"]);
var info = context.Cache[guid] as DownloadingFileInfo;
if (info != null)
{
info.Abort = abort;
context.Cache[guid] = info;
}
var doc = new XDocument();
var root = new XElement("root");
var flag = new XElement("flag", info == null ? "false" : "true");
root.Add(flag);
doc.Add(root);
context.Response.Write(doc.ToString());
context.Response.End();
}
public bool IsReusable
{
get { return false; }
}
}
}
好了，下面就是编写javascript脚本了，我引用了jquery这个框架，另外还用了ui框架。
核心代码是ajax-progress-upload.js文件，另外还有一个获取guid的文件。
$(document).ready(function () {
var _guid_url = "ProgressHandler/GenerateGuid.ashx";
var _progress_url = "ProgressHandler/Handler.ashx";
var _abort_url = "ProgressHandler/Abort.ashx";
var _target = "#guid";
var _guid = "";
var _cancel = false;
var _timer;
LJQ.setGuid(_target, _guid_url);
$("#upload_panel").draggable({ handle: "#upload_title" });
$("#upload_choose span").hover(function () {
$(this).css({
"color": "#f6af3a",
"border": "1px solid #e78f08"
});
}, function () {
$(this).css({
"color": "#1c94cd",
"border": "1px solid #ddd"
});
});
$("#upload_cancel").click(function () {
$.ajax({
url: _abort_url,
data: { guid: _guid, abort: true },
dataType: "xml",
type: "post",
success: function () {
$("#upload_panel").fadeOut('fast');
$("#back_panel").fadeOut(1000);
window.clearInterval(_timer);
}
});
});
$("#upload_submit").click(function () {
$("#upload_panel").fadeOut('fast');
$("#back_panel").fadeOut("1000");
});
$("form").submit(function () {
_guid = $(_target).val();
if ($("input[name='upload_file']").val() == "") {
alert("未指定上传文件！");
return false;
}
$("#upload_progress").css("width", "0%");
$("#finished_percent").html("准备上传...");
$("#upload_speed").html("");
$("#upload_fileName").html("");
$("#upload_fileSize").html("");
$("#upload_costTime").html("");
var _option = {
url: _progress_url,
data: { guid: _guid },
dataType: "xml",
type: "post",
beforeSend: function () {
$("#back_panel").fadeTo('fast', '0.5');
$("#upload_panel").fadeIn('1000');
},
success: function (response) {
if ($(response).find("root abort").text() == "true") {
$("#upload_panel").fadeOut('fast');
$("#back_panel").fadeOut(1000);
window.clearInterval(_timer);
}
else if ($(response).find("root none").text() == "no file") {
}
else {
var _percent = ($(response).find("root percent").text() * 100);
var _speed = $(response).find("root speed").text();
var _fileSize = $(response).find("root fileSize").text();
var _upload_costTime = $(response).find("root costTime").text();
if (parseInt(_speed) < 1024) {
_speed = LJQ.toFix(_speed) + "Kb";
} else {
_speed = LJQ.toFix(_speed / 1024) + "Mb";
}
if (parseInt(_fileSize) / 1024 < 1024) {
_fileSize = LJQ.toFix(_fileSize / 1024) + "Kb";
} else if (parseInt(_fileSize) / 1024 / 1024 < 1024) {
_fileSize = LJQ.toFix(_fileSize / 1024 / 1024) + "Mb";
} else {
_fileSize = LJQ.toFix(_fileSize / 1024 / 1024 / 1024) + "Gb";
}
if (_upload_costTime < 1000) {
_upload_costTime = _upload_costTime + "毫秒";
} else if (_upload_costTime / 1000 < 60) {
_upload_costTime = parseInt(_upload_costTime / 1000) + "秒" + _upload_costTime % 1000 + "毫秒";
} else {
_upload_costTime = parseInt(_upload_costTime / 1000 / 60) + "分" + parseInt((_upload_costTime % 60000) / 1000) + "秒" + _upload_costTime % 1000 + "毫秒";
}
$("#upload_progress").css("width", parseInt(_percent) + "%");
$("#finished_percent").html("完成百分比：" + LJQ.toFix(_percent) + "%");
$("#upload_speed").html("上传速度：" + _speed + "/sec");
$("#upload_fileName").html("文件名称：" + $(response).find("root fileName").text());
$("#upload_fileSize").html("文件大小：" + _fileSize);
$("#upload_costTime").html("上传耗时：" + _upload_costTime);
if (_percent >= 100) {
window.clearInterval(_timer);
$("#finished_percent").html("<span style='color:green;'>文件上传完成</span>");
}
if (_cancel) {
window.clearInterval(_timer);
}
}
},
error: function () { }
};
_timer = window.setInterval(function () { $.ajax(_option); }, 1000);
});
});
以上为代码的主要部分。asp.net单文件带进度条上传，不属于任务控件，也不是flash类型的上传，完全是asp.net、js、css实现上传。源码为开发测试版，需要使用的亲需要注意修改配置文件。
项目源码下载请点击这里：http://xiazai.haodaima.com/201509/yuanma/asp_net_progressbar(haodaima.com).rar
本文asp.net单文件带进度条上传的解决方案到此结束。幻想者头脑里只有空中楼阁，实干家胸中才有摩天大厦。小编再次感谢大家对我们的支持！