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How to: Add a New Document Part to an Office Open XML Package by Using the Open XML API

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The Office Open XML Package specification defines a set of XML files that contain the content and define the relationships for all of the document parts stored in a single package. These packages combine the parts that comprise the document files for Microsoft® Office Excel® 2007, Microsoft Office PowerPoint® 2007, and Microsoft Office Word 2007. The Open XML Application Programming Interface (API) allows you to create packages and manipulate the files that comprise the packages. This topic walks through the code and steps to add a document part (file) to an Office Open XML package in Office Word 2007, although the steps are the same for each of the three 2007 Microsoft Office system programs that support the Office Open XML Format.


The code samples in this topic are in Microsoft Visual Basic® .NET and Microsoft Visual C#®. You can use them in an add-in created in Microsoft Visual Studio® 2008. For more information about how to create an add-in in Visual Studio 2008, see Getting Started with the Open XML Format SDK 1.0.

In the following code, you add a new document part containing custom XML from an external file and then populate the part.

// How to add a new document part to a package.
public static void AddNewPart(string document, string fileName)
   using (WordprocessingDocument wordDoc = WordprocessingDocument.Open(document, true))
      MainDocumentPart mainPart = wordDoc.MainDocumentPart;
      CustomXmlPart myXmlPart = mainPart.AddNewPart<CustomXmlPart>();

      using (FileStream stream = new FileStream(fileName, FileMode.Open))

To add a new document part containing custom XML from an external file and populate the document part

  1. In this procedure, first you pass in parameters representing the path to and the name of the source Word 2007 document as well as the file containing the custom XML.

  2. Then you open the document as a WordprocessingDocument object.

  3. Next, you create a reference to the MainDocumentPart part and add a new custom XML part (named item.xml).

  4. Finally, you read the contents of the external file containing the custom XML and write it to the CustomXmlPart part.


    To use the new document part in the document, you need to add a link to the document part in the relationship part for the new part.