Asp.Net文件的上传和下载

2026-04-08 20:32:06

1、aspx页面：

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="上传和下载文件.aspx.cs" Inherits="上传和下载文件" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

</head>

<body>

<asp:FileUpload ID="homeworkFile" runat="server" />

<asp:Button ID="btnAdd" runat="server" Text="上传" OnClick="btnAdd_Click"/></br>

<asp:Button ID="btndownfile" runat="server" Text="下载方法一：TransmitFile"

onclick="btndownfile_Click" /></br>

<asp:Button ID="btndownfilebyWriteFile" runat="server"

Text="下载方法二：WriteFile" onclick="btndownfilebyWriteFile_Click" /></br>

<asp:Button ID="btndownfilebyWriteFile2" runat="server"

Text="下载方法三：WriteFile分块" onclick="btndownfilebyWriteFile2_Click" /><br />

<asp:Button ID="btndownfilebystream" runat="server" Text="下载方法四：流方式下载"

onclick="btndownfilebystream_Click" />

</form>

</body>

</html>

2、aspx后台代码：

using System;

using System.Collections;

using System.Configuration;

using System.Data;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;

using System.IO;

public partial class 上传和下载文件 : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

}

protected void btnAdd_Click(object sender, EventArgs e)

{

//文件原名

string fileName = Path.GetFileName(this.homeworkFile.FileName);

//文件新名字=文件原名+当前时间

string newFileName = fileName.Substring(0, fileName.IndexOf('.')) + DateTime.Now.ToString("yyyyMMddhhmmss");

//给文件名加后缀名

newFileName += fileName.Substring(fileName.IndexOf('.'), fileName.Length - fileName.IndexOf('.'));

//获得文件存储的路径名

string Url = ConfigurationManager.AppSettings["ResoursePath"] + ConfigurationManager.AppSettings["RESHomeworkContentPath"] + @"\" + newFileName;

//验证文件大小

if (this.IsFileSizeLessMax())

{ //验证文件的类型

if (this.isTypeOk(Url))

{

//验证文件存储的路径是否存在

string pathStr = ConfigurationManager.AppSettings["ResoursePath"] + ConfigurationManager.AppSettings["RESHomeworkContentPath"];

if (!Directory.Exists(pathStr)) //如果不存在路径

{

Directory.CreateDirectory(pathStr); //创建路径

}

if (!Url.Equals("")) //如果有上传文件

{

FileUpload fileUpLoad = new FileUpload();

//1.存放文件

// fileUpLoad.SaveAs(Url);

homeworkFile.PostedFile.SaveAs(Url);

}

/// <summary>

/// 验证上传文件是否超过规定的最大值

/// </summary>

/// <returns></returns>

private bool IsFileSizeLessMax()

{

//返回值

bool result = false;

if (this.homeworkFile.HasFile) //如果上传了文件

{

//获取上传文件的允许最大值

long fileMaxSize = 1024 * 1024;

try

{

fileMaxSize *= int.Parse(ConfigurationManager.AppSettings["FileUploadMaxSize"].Substring(0, ConfigurationManager.AppSettings["FileUploadMaxSize"].Length - 1));

}

catch (Exception ex)

{

//this.WriteException("UserPotal:Homework", ex);

}

if (this.homeworkFile.PostedFile.ContentLength > int.Parse(fileMaxSize.ToString())) //如果文件大小超过规定的最大值

{

//this.ShowMessage("文件超过规定大小。");

}

else

{

result = true;

}

else //如果没有上传的文件

{

result = true;

}

return result;

}

/// <summary>

/// 验证文件类型的方法

/// </summary>

/// <param name="fileName"></param>

/// <returns></returns>

private bool isTypeOk(string fileName)

{

//返回结果

bool endResult = false;

//验证结果

int result = 0;

if (!fileName.Equals("")) //如果有上传文件

{

//允许的文件类型

string[] fileType = null;

try

{

fileType = ConfigurationManager.AppSettings["FileType"].Split(',');

}

catch (Exception ex)

{

//this.ShowMessage("获取配置文件信息出错");

//this.WriteException("AdminProtal:Homework", ex);

}

fileName = fileName.Substring(fileName.LastIndexOf('.'), fileName.Length - fileName.LastIndexOf('.'));

for (int i = 0; i < fileType.Length; i++)

{

if (fileType[i].Equals(fileName)) //如果是合法文件类型

{

result++;

}

if (result > 0)

{

endResult = true;

}

else //如果没有上传文件

{

endResult = true;

}

return endResult;

}

//下载方法一

protected void btndownfile_Click(object sender, EventArgs e)

{

/* 微软为Response对象提供了一个新的方法TransmitFile来解决使用Response.BinaryWrite 下载超过400mb的文件时导致Aspnet_wp.exe进程回收而无法成功下载的问题。代码如下： */

Response.ContentType = "application/x-zip-compressed";

Response.AddHeader("Content-Disposition", "attachment;filename=DBintegrate20120521030107.txt");

string filename = Server.MapPath("BJNetwork/Data/DBintegrate20120521030107.txt");

Response.TransmitFile(filename);

}

//下载方法二

protected void btndownfilebyWriteFile_Click(object sender, EventArgs e)

{

/* using System.IO; */

string fileName = "DBintegrate20120521030107.txt";//客户端保存的文件名

string filePath = Server.MapPath("BJNetwork/Data/DBintegrate20120521030107.txt");//路径

FileInfo fileInfo = new FileInfo(filePath);

Response.Clear();

Response.ClearContent();

Response.ClearHeaders();

Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);

Response.AddHeader("Content-Length", fileInfo.Length.ToString());

Response.AddHeader("Content-Transfer-Encoding", "binary");

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

Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");

Response.WriteFile(fileInfo.FullName);

Response.Flush();

Response.End();

}

//下载方法三

protected void btndownfilebyWriteFile2_Click(object sender, EventArgs e)

{

string fileName = "前台老师和学生界面对比20120521034329.rar";//客户端保存的文件名

string filePath = Server.MapPath("BJNetwork/Data/前台老师和学生界面对比20120521034329.rar");//路径

System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath);

if (fileInfo.Exists == true)

{

const long ChunkSize = 102400;//100K 每次读取文件，只读取100K，这样可以缓解服务器的压力

byte[] buffer = new byte[ChunkSize];

Response.Clear();

System.IO.FileStream iStream = System.IO.File.OpenRead(filePath);

long dataLengthToRead = iStream.Length;//获取下载的文件总大小

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

Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName));

while (dataLengthToRead > 0 && Response.IsClientConnected)

{

int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小 Response.OutputStream.Write(buffer, 0, lengthRead);

Response.Flush();

dataLengthToRead = dataLengthToRead - lengthRead;

}

Response.Close();

}

//下载方法四

protected void btndownfilebystream_Click(object sender, EventArgs e)

{

string fileName = "前台老师和学生界面对比20120521034329.rar";//客户端保存的文件名

string filePath = Server.MapPath("BJNetwork/Data/前台老师和学生界面对比20120521034329.rar");//路径 //以字符流的形式下载文件

FileStream fs = new FileStream(filePath, FileMode.Open);

byte[] bytes = new byte[(int)fs.Length];

fs.Read(bytes, 0, bytes.Length);

fs.Close();

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

//通知浏览器下载文件而不是打开

Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));

Response.BinaryWrite(bytes);

Response.Flush();

Response.End();

}

3、web配置文件：

<system.web>  <httpRuntime executionTimeout="300" maxRequestLength="409600" useFullyQualifiedRedirectUrl="false"/>

</system.web>

IIS中上传大小的修改

1、首先要到进程中把IIS服务关了，即把inetinfo.exe进程关了，不然里面的文件不给你更改的哟~~~ 2、在系统目录中找到：windows/system32/inesrv/metabase.xml”文件，找个文本编辑器打开他，我都用EditPuls（这家伙不错，带字体色彩的），Ctrl+F 找到AspMaxRequestEntityAllowed="204800"这一项，这就是iis上传文件的默认大小了，默认为204800Byte，也就是200KB，将它改为你需要的大小就可以了！

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