无效pdfexception未找到pdf标头签名
我有一些代码可以读取 pdf 文件。该代码在以下行中失败：
I have some code that reads pdf files. The code fails at the line :
iTextSharp.text.pdf.PRTokeniser.CheckPdfHeader() at
iTextSharp.text.pdf.PdfReader.ReadPdf()
我从其他条目中得知此问题来自某些无效格式化为pdf。但是我不能告诉我的用户重做他们的pdf。有没有其他方法来解决这个问题，即使出现这个问题，还是可以读取pdf吗？
I know from other entries that this issue is coming from some invalid formatting in the pdf. However I'm not in a position to tell my users to redo their pdfs. Is there some other way around this issue, that can allow reading of the pdf despite this problem?
如果文件没有'从％PDF开始 - 然后没有什么可修复的：文件不是PDF文件。
If a file doesn't start with %PDF- then there's nothing to fix: the file isn't a PDF file.
然而，可能还有另一个问题：也许你正试图在创建InputStream时，由于某些问题，访问长度为零的文件。我看到这种情况发生的另一个背景是从服务器加载的PDF，其中服务器以HTML而不是PDF文件返回404消息; - ）
However, there may be another problem: maybe you're trying to access a file that has zero length due to some problem while creating the InputStream. Another context in which I've seen this happen, is a PDF loaded from a server, where the server returned a 404 message in HTML instead of a PDF file ;-)
每当发生异常时，您应该将字节存储在某处，并检查它们。没有这些字节，没有人能够给你有用的建议。
Whenever that exception happens, you should store the bytes somewhere, and examine them. Without those bytes, nobody will be able to give you useful advice.