最近学习了 C#实现文件上传与下载，现在分享给大家。

1、C#文件上传

创建MyUpload.htm页面，用于测试

<form name="form1" method="post" action="UploadFile.aspx" id="form1" enctype="multipart/form-data"> <input type="file" id="txtFile" name="picfile" /></br> <input type="submit" value="上传" /> </form>

创建UploadFile.aspx文件，在UploadFile.aspx.cs键入如下代码：

Random rnd = new Random(); //产生随机数 private string _directory = @"/File/UploadFile"; //目录 protected void Page_Load(object sender, EventArgs e) { try { if (RequestFilesCount > 0) { //判断文件大小 int length = RequestFiles[0]ContentLength; if (length > 1048576) { ResponseWrite("文件大于1M，不能上传"); return; } string type = RequestFiles[0]ContentType; string fileExt = PathGetExtension(RequestFiles[0]FileName)ToLower(); //只能上传图片，过滤不可上传的文件类型 string fileFilt = "gif|jpg|php|jsp|jpeg|png|"; if (fileFiltIndexOf(fileExt) <= -1) { ResponseWrite("对不起！请上传图片！！"); return; } else { string fileName = ServerMapPath(_directory) + "" + DateTimeNowToString("yyyyMMddHHmmssfff") + rndNext(10, 99)ToString() + fileExt; RequestFiles[0]SaveAs(fileName); ResponseWrite("上传成功！"); } } } catch { throw new Exception(); } }

2 、C#文件下载

创建DownloadFile.aspx，在DownloadFile.aspx.cs键入如下方法：

/// <summary> /// C#文件下载 /// </summary> /// <param name="filename"></param> public void MyDownload(string filename) { string path = ServerMapPath("/File/"+filename); if(!FileExists(path)) { ResponseWrite("对不起！文件不存在！！"); return; } SystemIOFileInfo file = new SystemIOFileInfo(path); string fileFilt="asp|aspx|php|jsp|ascx|config|asa|"; //不可下载的文件，务必要过滤干净 string fileName = fileName; string fileExt = fileNameSubstring(filenameLastIndexOf(""))Trim()ToLower(); if(fileFiltIndexOf(fileExt)!=-1) { ResponseWrite("对不起！该类文件禁止下载！！"); } else { ResponseClear(); ResponseAddHeader("Content-Disposition", "attachment; filename=" + HttpUtilityUrlEncode(fileName)); ResponseAddHeader("Content-Length", fileLengthToString()); ResponseContentType = GetContentType(HttpUtilityUrlEncode(fileExt)); ResponseWriteFile(fileFullName); ResponseEnd(); } } /// <summary> /// 获取下载类型 /// </summary> /// <param name="fileExt"></param> /// <returns></returns> public string GetContentType(string fileExt) { string ContentType; switch (fileExt) { case "asf": ContentType = "video/x-ms-asf"; break; case "avi": ContentType = "video/avi"; break; case "doc": ContentType = "application/msword"; break; case "zip": ContentType = "application/zip"; break; case "xls": ContentType = "application/vndms-excel"; break; case "gif": ContentType = "image/gif"; break; case "jpg": ContentType = "image/jpeg"; break; case "jpeg": ContentType = "image/jpeg"; break; case "wav": ContentType = "audio/wav"; break; case "mp3": ContentType = "audio/mpeg3"; break; case "mpg": ContentType = "video/mpeg"; break; case "mepg": ContentType = "video/mpeg"; break; case "rtf": ContentType = "application/rtf"; break; case "html": ContentType = "text/html"; break; case "htm": ContentType = "text/html"; break; case "txt": ContentType = "text/plain"; break; default: ContentType = "application/octet-stream"; break; } return ContentType; }

*如何获取现有文件的ContentType属性

/// <summary> /// 获取现有文件的ContentType属性 /// </summary> /// <param name="filename"></param> /// <returns></returns> public string GetFileContentType(string filename) { string[] array = filenameSplit(''); string result = stringEmpty; string suffix = "" + array[arrayLength - 1]; MicrosoftWinRegistryKey rg = MicrosoftWinRegistryClassesRootOpenSubKey(suffix); object obj = rgGetValue("Content Type"); result = obj != null ? objToString() : stringEmpty; rgClose(); return result; }

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持查字典教程网。