有一个非常非常好的机会，你不能这样做. .NET框架有一个内置的限制，即任何单个对象都不能超过2GB.由于iTextSharp是用C#编写的，因此iTextSharp很有可能达到该限制，特别是如果您对不超过2Gb的类似文件没有问题的话.
可能值得看看 iText网站 [ ^ ]，看看是否还有其他人正在解决此问题.

There is a very, very good chance that you can''t. The .NET framework has a built in limitation, that no single object can exceed 2GB. Since iTextSharp is written in C#, it is quite possible that iTextSharp is hitting that limit, particularly if you are not having a problem with similar files that do not exceed 2Gb.
It may be worth having a look at the iText website[^] and seeing if anyone else is hitting this problem.