根据二进制流判断上传文件类型是否合法代码,CSharp代码库,德仔网

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【CSharp】根据二进制流判断上传文件类型是否合法

作者:Dezai.CN / 发布于2012/8/23/ 721

根据二进制流判断上传文件类型是否合法

<div>using System;
using System.Collections.Generic;
using  System.Linq;
using System.Web;
using System.Web.UI;
using  System.Web.UI.WebControls;
using System.IO;

public partial class  niunantest : System.Web.UI.Page
{
protected void Page_Load(object  sender, EventArgs e)
{

}
protected void  Button1_Click(object sender, EventArgs e)
{
string str =  FileUpload1.PostedFile.ContentType;
Response.Write("文件类型："+str);

string filename =  "";

FileExtension[] fe = { FileExtension.GIF, FileExtension.JPG,  FileExtension.PNG };
if  (FileValidation.IsAllowedExtension(FileUpload1, fe))
{
string fileExt =  System.IO.Path.GetExtension(FileUpload1.FileName).ToLower();
Response.Write("验证通过！");
//filename = "/Images/" +  DateTime.Now.ToString("yyyyMMddHHmmss") +  fileExt;
//FileUpload1.PostedFile.SaveAs(Server.MapPath(filename));
}
else
{
Response.Write(  "验证不通过，只支持以下格式的图片：JPG,GIF,PNG");
return;
}

}

public enum FileExtension
{
JPG =  255216,
GIF = 7173,
PNG = 13780,
SWF =  6787,
RAR = 8297,
ZIP = 8075,
_7Z =  55122

// 255216 jpg;

// 7173  gif;

// 6677 bmp,

// 13780 png;

//  6787 swf

// 7790 exe dll,

// 8297  rar

// 8075 zip

// 55122 7z

// 6063  xml

// 6033 html

// 239187 aspx

//  117115 cs

// 119105 js

// 102100  txt

// 255254 sql 

}

public class  FileValidation
{
public static bool  IsAllowedExtension(FileUpload fu, FileExtension[] fileEx)
{
int fileLen =  fu.PostedFile.ContentLength;
byte[] imgArray = new  byte[fileLen];
fu.PostedFile.InputStream.Read(imgArray, 0,  fileLen);
MemoryStream ms = new  MemoryStream(imgArray);
System.IO.BinaryReader br = new  System.IO.BinaryReader(ms);
string fileclass =  "";
byte buffer;
try
{
buffer = br.ReadByte();
fileclass =  buffer.ToString();
buffer =  br.ReadByte();
fileclass +=  buffer.ToString();
}
catch
{
}
br.Close();
ms.Close();
foreach (FileExtension fe in fileEx)
{
if (Int32.Parse(fileclass) ==  (int)fe)
return true;
}
return false;
}
}
}

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　判断上传文件类型　

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