C#实现文件上传与下载功能实例

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

参考文章：http://blog.ncmem.com/wordpress/2023/11/01/c%e5%ae%9e%e7%8e%b0%e6%96%87%e4%bb%b6%e4%b8%8a%e4%bc%a0%e4%b8%8e%e4%b8%8b%e8%bd%bd%e5%8a%9f%e8%83%bd%e5%ae%9e%e4%be%8b/

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