I want to validate the file type to make sure the user is uploading an image of type JPEG, GIF, or PNG. Instead of checking the file extension, I figured using HttpPostedFile.ContentType would be safer since it checks the MIME content type.
protected void cvValidateImageType_ServerValidate(object source, ServerValidateEventArgs args)
{
if (fupImage.HasFile)
{
args.IsValid = (fupImage.PostedFile.ContentType.ToLower() == "image/jpg" ||
fupImage.PostedFile.ContentType.ToLower() == "image/jpeg" ||
fupImage.PostedFile.ContentType.ToLower() == "image/pjpeg" ||
fupImage.PostedFile.ContentType.ToLower() == "image/gif" ||
fupImage.PostedFile.ContentType.ToLower() == "image/x-png" ||
fupImage.PostedFile.ContentType.ToLower() == "image/png");
}
else
args.IsValid = true;
}
Is this a flawless way to check the file type, or can it be fooled?
See Question&Answers more detail:
os 与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…