Introducing WmlComparer, a Module in Open-Xml-PowerTools

WmlComparer compares two Open XML documents, producing a new document that contains the precise differences in revision tracking markup. You can then iterate through those differences.

This module contains my latest thinking on how to process large documents character-by-character. The module converts the DOCX into a new form – an array – where every item in the array is a single piece of content, whether it be a character in a paragraph, the paragraph mark itself, an image, and so on. This thinking will go into the next version of OpenXmlRegex, so that it will be possible to include new lines in the search string, as well as replace matched strings with content that contains new lines.

This module is extremely useful when writing XUnit tests for code that processes Open XML markup – we can test that the code produced the exact document that we intended.



  1. Jon Silberman said,

    November 21, 2016 @ 3:16 pm


    We are looking for some help with an open office XML problem in our development project.

    Can you give me a call or shoot me an email to discuss

    713 985 4620 … office phone — email is



  2. Jimmy said,

    March 20, 2018 @ 2:09 pm

    Hi Eric,

    Same for us here… We convert a simple document to html and the result for some reasons is not the same at all. Can you pls send me an email to forward more details?



  3. Eric White said,

    March 20, 2018 @ 2:25 pm

    Hi Jim,

    Can you send an email to

    Thanks, Eric

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