数百页的 C# 中的 Word/PDF 生成速度太慢

Question

I'm having speed issue generating documentation in C#.

I am basically trying to create documents with 600+ pages. But the tools I have used handle this very slowly.

I first tried using DocX by Novacode. Creation of this document with 600+ pages takes upwards to 3 minutes. I learned that there could be an issue with the function "InsertDocument" so I tried to find a different solution.

I started looking into opening a HTML document into word. While this is a fast solution, images are not embedded into the document. The HTML syntax (src="data:image/png;base64,xxxx") is not supported in MS Word.

I could use URLs to the images, but then if the internet connection is down, the images would not display.

I then started looking into a HTML->PDF solution. iTextSharp is a little faster than the DocX solution, but still takes 1-2 minutes to generate this document.

I am simply out of ideas. I'm not sure a commercial product would be better, and I don't want to shell out that kind of cash, to just have the same speed issue.

Has anyone had experience with creating Word/PDF documents with 600+ pages in C# that is fairly quick (1-5 seconds).

Answer 1

You should be able to create a rich formatted DOCX file with 600+ pages in that time frame, but for PDF file I'm not sure... it will probably depend on your document content.

Anyway, I'm able to create a rather large DOCX file with GemBox.Document in just few seconds (0-4 sec), and PDF file as well, but it does take a bit more time then DOCX output.

You can also convert HTML to DOCX or HTML to PDF really fast, but that can depend on the HTML content itself.

If possible, you should prefer having well written HTML content that's "printer-friendly", doesn't have too much nesting levels, has optimized images, has single CSS file, etc. Also, if you're providing an URL as an input path then I think it's better to have embedded base64 images then links in order to avoid making additional web requests.

Last, I don't think there is much difference in Flat OPC XML vs DOCX. Basically they both generate the same content, it's just that DOCX file is additionally zipped which is a neglectable performance penalty.

Answer 2

If you are trying to do this from a web server, you should be careful about resources consumption of this process, since you may run out of memory for example quite easily.

If at some point you decide to consider commercial libraries, maybe you could give Amyuni PDF Creator .Net a try. Amyuni PDF Creator .Net provides a "page by page" mode that saves resources when processing exceptionally long PDF documents. The idea is to save each page to the output file as soon as it is generated, maybe keeping a few pages in memory in case they need to be modified.

Take a look on these links for more details:

• SartSave Method
• EndSave Method
• Processing large PDF files

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