Code
1 //实现IHttpModule接口
2 public class HttpUploadModule : IHttpModule
3 {
4 public HttpUploadModule()
5 {
6
7 }
8
9 public void Init(HttpApplication application)
10 {
11 //订阅事件
12 application.BeginRequest += new EventHandler(this.Application_BeginRequest);
13 }
14
15 public void Dispose()
16 {
17 }
18
19 private void Application_BeginRequest(Object sender, EventArgs e)
20 {
21 HttpApplication app = sender as HttpApplication;
22 HttpWorkerRequest request = GetWorkerRequest(app.Context);
23 Encoding encoding = app.Context.Request.ContentEncoding;
24
25 int bytesRead = 0; // 已读数据大小
26 int read; // 当前读取的块的大小
27 int count = 8192; // 分块大小
28 byte[] buffer; // 保存所有上传的数据
29
30 if (request != null)
31 {
32 // 返回 HTTP 请求正文已被读取的部分。
33 byte[] tempBuff = request.GetPreloadedEntityBody(); //要上传的文件
34
35 // 如果是附件上传
36 if (tempBuff != null && IsUploadRequest(app.Request)) //判断是不是附件上传
37 {
38 // 获取上传大小
39 //
40 long length = long.Parse(request.GetKnownRequestHeader(HttpWorkerRequest.HeaderContentLength));
41
42 buffer = new byte[length];
43 count = tempBuff.Length; // 分块大小
44
45 // 将已上传数据复制过去
46 //
47 Buffer.BlockCopy(tempBuff, //源数据
48 0, //从0开始读
49 buffer, //目标容器
50 bytesRead, //指定存储的开始位置
51 count); //要复制的字节数。
52
53
54 // 开始记录已上传大小
55 bytesRead = tempBuff.Length;
56
57 // 循环分块读取，直到所有数据读取结束
58 while (request.IsClientConnected() &&!request.IsEntireEntityBodyIsPreloaded() && bytesRead < length)
59 {
60 // 如果最后一块大小小于分块大小，则重新分块
61 if (bytesRead + count > length)
62 {
63 count = (int)(length - bytesRead);
64 tempBuff = new byte[count];
65 }
66
67 // 分块读取
68 read = request.ReadEntityBody(tempBuff, count);
69
70 // 复制已读数据块
71 Buffer.BlockCopy(tempBuff, 0, buffer, bytesRead, read);
72
73 // 记录已上传大小
74 bytesRead += read;
75
76 }
77 if ( request.IsClientConnected() && !request.IsEntireEntityBodyIsPreloaded() )
78 {
79 // 传入已上传完的数据
80 InjectTextParts(request, buffer);
81 }
82 }
83 }
84 }
85
86
87 HttpWorkerRequest GetWorkerRequest(HttpContext context)
88 {
89
90 IServiceProvider provider = (IServiceProvider)HttpContext.Current;
91 return (HttpWorkerRequest)provider.GetService(typeof(HttpWorkerRequest));
92 }
93
94 /// <summary>
95 /// 传入已上传完的数据
96 /// </summary>
97 /// <param name="request"></param>
98 /// <param name="textParts"></param>
99 void InjectTextParts(HttpWorkerRequest request, byte[] textParts)
100 {
101 BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.NonPublic;
102
103 Type type = request.GetType();
104
105 while ((type != null) && (type.FullName != "System.Web.Hosting.ISAPIWorkerRequest"))
106 {
107 type = type.BaseType;
108 }
109
110 if (type != null)
111 {
112 type.GetField("_contentAvailLength", bindingFlags).SetValue(request, textParts.Length);
113 type.GetField("_contentTotalLength", bindingFlags).SetValue(request, textParts.Length);
114 type.GetField("_preloadedContent", bindingFlags).SetValue(request, textParts);
115 type.GetField("_preloadedContentRead", bindingFlags).SetValue(request, true);
116 }
117 }
118
119 private static bool StringStartsWithAnotherIgnoreCase(string s1, string s2)
120 {
121 return (string.Compare(s1, 0, s2, 0, s2.Length, true, CultureInfo.InvariantCulture) == 0);
122 }
123
124 /// <summary>
125 /// 是否为附件上传
126 /// 判断的根据是ContentType中有无multipart/form-data
127 /// </summary>
128 /// <param name="request"></param>
129 /// <returns></returns>
130 bool IsUploadRequest(HttpRequest request)
131 {
132 return StringStartsWithAnotherIgnoreCase(request.ContentType, "multipart/form-data");
133 }
134 }
3.用法
（1）修改web.config
1 <httpModules>
2 <add name="HttpUploadModule"
3 type="HttpModelApp.HttpUploadModule, HttpModelApp" />
4
5 </httpModules>
6 <httpRuntime
7 maxRequestLength="2000000"
8 executionTimeout="300"
9 /> (2)aspx
1 <form id="form1" runat="server" encType="multipart/form-data" method="post">
2 <div>
3 <INPUT id="firstFile" type="file" name="firstFile" runat="server">
4 <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="上传" />
5 <asp:Label ID="Label1" runat="server"></asp:Label></div>
6 </form> (3)aspx.cs
1 protected void Button1_Click(object sender, EventArgs e)
2 {
3 //要保存的位置
4 string strDesPath = "D:\\";
5 string strFileName = this.firstFile.PostedFile.FileName;
6 strFileName =strDesPath + strFileName.Substring(strFileName.LastIndexOf("\\"));
7 //
8 this.firstFile.PostedFile.SaveAs(strFileName);
9 this.Label1.Text = "文件保存到了：" + strFileName;
10 }
4.大文件上传的限制
虽然可以上传大文件，但是这个大小也是有限制的，不能超过2G的大小。
还有啊,大家不要忘记了导入命名空间.
using System;
using System.Collections;
using System.Collections.Specialized;
using System.Globalization;
using System.IO;
using System.Text;
using System.Web;
using System.Reflection;
web.config文件如下
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<appSettings/>
<connectionStrings/>
<system.web>
<!--
设置 compilation debug="true" 将调试符号插入
已编译的页面中。但由于这会
影响性能，因此只在开发过程中将此值
设置为 true。
-->
<compilation debug="true" />
<!--
通过 <authentication> 节可以配置 ASP.NET 使用的
安全身份验证模式，
以标识传入的用户。
-->
<authentication mode="Windows" />
<!--
如果在执行请求的过程中出现未处理的错误，
则通过 <customErrors> 节可以配置相应的处理步骤。具体说来，
开发人员通过该节可以配置
要显示的 html 错误页
以代替错误堆栈跟踪。
<customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm">
<error statusCode="403" redirect="NoAccess.htm" />
<error statusCode="404" redirect="FileNotFound.htm" />
</customErrors>
-->
<httpModules>
<add name="HttpUploadModule"
type="HttpModelApp.HttpUploadModule, HttpModelApp" />
</httpModules>
<httpRuntime
maxRequestLength="2000000"
executionTimeout="300"
/>
</system.web>
</configuration>