读取每个文件的头两个字节，
byte[0].ToString()+byte[1].ToString()的值
255216:jpg,7173:gif,6677:bmp,13780:png
private bool IsPicture(string filePath)//filePath是文件的完整路径
{
try
{
FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
BinaryReader reader = new BinaryReader(fs);
string fileClass;
byte buffer;
byte[] b=new byte[2];
buffer = reader.ReadByte();
b[0] = buffer;
fileClass = buffer.ToString();
buffer = reader.ReadByte();
b[1]=buffer;
fileClass += buffer.ToString();
reader.Close();
fs.Close();
if (fileClass == "255216 ")//255216是jpg;7173是gif;6677是BMP,13780是PNG;7790是exe,8297是rar
{
return true;
}
else
{
return false;
}
}
catch
{
return false;
}
}
c#判断文件是否是图片
标签: FileStream ReadByte
ccdot写于2008-9-17 13:39:29
protected static bool IsValidGif(byte[] source)
{
if (source == null || source.Length < 6)
return false;
byte[] GIF = new byte[6];
GIF[0] = 0x47;
GIF[1] = 0x49;
GIF[2] = 0x46;
GIF[3] = 0x38;
GIF[4] = 0x39;
GIF[5] = 0x61;
bool valid = true;
int nIndex = 0;
foreach(byte bTmp in GIF)
{
if(bTmp!=source[nIndex])
{
valid = false;
break;
}
nIndex++;
}
return valid;
}
protected static bool IsValidJpgOrJpeg(byte[] source)
{
if (source == null || source.Length < 10)
return false;
byte[] Jpg=new byte[4];
Jpg[0] = 0xff;
Jpg[1] = 0xd8;
Jpg[2] = 0xff;
Jpg[3] = 0xd9;
if (source[0] == Jpg[0] && source[1] == Jpg[1] && source[source.Length - 2] == Jpg[2] && source[source.Length - 1] == Jpg[3])
return true;
else
return false;
}
写于 2008-9-17 13:53:50#1
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