Office 2007 Open XML global string replace (C#)

[edit: If you're dealing exclusively with Excel, all strings are in /sharedStrings.xml. However, this is not generally true of all Office 2007 docs across the board. See
http://www.rootsilver.com/2008/11/openxml-excel-vs-word---string for more details. This solution/hack works with all OpenXml docs.]

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You can spend a lot of time parsing really ugly XML in Office 2007 documents.
[edit: for example, just found this: http://msdn.microsoft.com/en-us/library/cc974107.aspx]

Or, you can do something like this: a global string replace in all the xml files packaged within the .pptx, .xlsx, or .docx files (they're really just .zip files).

For my purposes, I used this code to replace the URL in linked files (i.e. "Paste special") in Power Point files: I can use this code to chug through a stack of pptx files, replacing the url. However, it's generally useful for replacing random regex-able text within word, powerpoint, or excel 2007 documents.



... replaced text:

using System;
using System.Xml;
using System.IO;
using System.Text.RegularExpressions;
using System.IO.Packaging; //C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\windowsbase.dll

public class ReplacementUtility {
  public static void Main {
    ReplacementUtility utility = new ReplacementUtility();

    //Word 2007
    string templateFile = "c:\\template.docx";
    string newFile = "c:\\widgets.docx";

    File.Copy(templateFile, newFile);
    utility.UpdateOpenXmlDocument(newFile, "Acme Inc", "Wally's Widgets");

    //Excel 2007
    templateFile = "c:\\template.pptx";
    newFile = "c:\\widgets.pptx";

    File.Copy(templateFile, newFile);
    utility.UpdateOpenXmlDocument(newFile, "Acme Inc", "Wally's Widgets");

  }

  public void UpdateOpenXmlDocument(string fileName, string searchRegexp, string replacement) {
     Regex regex = new Regex(searchRegexp, RegexOptions.Multiline|RegexOptions.IgnoreCase);

    using (Package package = Package.Open(fileName, FileMode.Open, FileAccess.ReadWrite)) {
      foreach (PackagePart part in package.GetParts()) {
        if (part.Uri.ToString().IndexOf(".xml") != -1 
		|| 
		part.Uri.ToString().IndexOf(".rels") != -1) {
          XmlDocument document = new XmlDocument();

          document.Load(part.GetStream());

          if (regex.IsMatch(document.InnerXml)) {
            document.InnerXml = regex.Replace(document.InnerXml, replacement);

            document.Save(part.GetStream(FileMode.Create, FileAccess.Write));
          }
        }
      }
    }
  }
}