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Get the contents of a document part from a package

  • Artykuł

This topic shows how to use the classes in the Open XML SDK for Office to retrieve the contents of a document part in a Wordprocessing document programmatically.

Packages and Document Parts

An Open XML document is stored as a package, whose format is defined by ISO/IEC 29500-2. The package can have multiple parts with relationships between them. The relationship between parts controls the category of the document. A document can be defined as a word-processing document if its package-relationship item contains a relationship to a main document part. If its package-relationship item contains a relationship to a presentation part it can be defined as a presentation document. If its package-relationship item contains a relationship to a workbook part, it is defined as a spreadsheet document. In this how-to topic, you will use a word-processing document package.

Getting a WordprocessingDocument Object

The code starts with opening a package file by passing a file name to one of the overloaded Open() methods (Visual Basic .NET Shared method or C# static method) of the WordprocessingDocument class that takes a string and a Boolean value that specifies whether the file should be opened in read/write mode or not. In this case, the Boolean value is false specifying that the file should be opened in read-only mode to avoid accidental changes.

    // Open a Wordprocessing document for editing.
    using (WordprocessingDocument wordDoc = WordprocessingDocument.Open(document, false))
    {
          // Insert other code here.
    }

The using statement provides a recommended alternative to the typical .Create, .Save, .Close sequence. It ensures that the Dispose method (internal method used by the Open XML SDK to clean up resources) is automatically called when the closing brace is reached. The block that follows the using statement establishes a scope for the object that is created or named in the using statement, in this case wordDoc. Because the WordprocessingDocument class in the Open XML SDK automatically saves and closes the object as part of its System.IDisposable implementation, and because the Dispose method is automatically called when you exit the block; you do not have to explicitly call Save and Close─as long as you use using.

Structure of a WordProcessingML Document

The basic document structure of a WordProcessingML document consists of the document and body elements, followed by one or more block level elements such as p, which represents a paragraph. A paragraph contains one or more r elements. The r stands for run, which is a region of text with a common set of properties, such as formatting. A run contains one or more t elements. The t element contains a range of text. The following code example shows the WordprocessingML markup for a document that contains the text "Example text."

    <w:document xmlns:w="https://schemas.openxmlformats.org/wordprocessingml/2006/main">
      <w:body>
        <w:p>
          <w:r>
            <w:t>Example text.</w:t>
          </w:r>
        </w:p>
      </w:body>
    </w:document>

Using the Open XML SDK, you can create document structure and content using strongly-typed classes that correspond to WordprocessingML elements. You will find these classes in the DocumentFormat.OpenXml.Wordprocessing namespace. The following table lists the class names of the classes that correspond to the document, body, p, r, and t elements.

WordprocessingML Element Open XML SDK Class Description
document Document The root element for the main document part.
body Body The container for the block level structures such as paragraphs, tables, annotations and others specified in the ISO/IEC 29500 specification.
p Paragraph A paragraph.
r Run A run.
t Text A range of text.

For more information about the overall structure of the parts and elements of a WordprocessingML document, see Structure of a WordprocessingML document.

Comments Element

In this how-to, you are going to work with comments. Therefore, it is useful to familiarize yourself with the structure of the <comments> element. The following information from the ISO/IEC 29500 specification can be useful when working with this element.

This element specifies all of the comments defined in the current document. It is the root element of the comments part of a WordprocessingML document.Consider the following WordprocessingML fragment for the content of a comments part in a WordprocessingML document:

    <w:comments>
      <w:comment … >
        …
      </w:comment>
    </w:comments>

The comments element contains the single comment specified by this document in this example.

© ISO/IEC29500: 2008.

The following XML schema fragment defines the contents of this element.

    <complexType name="CT_Comments">
       <sequence>
           <element name="comment" type="CT_Comment" minOccurs="0" maxOccurs="unbounded"/>
       </sequence>
    </complexType>

How the Sample Code Works

After you have opened the source file for reading, you create a mainPart object by instantiating the MainDocumentPart. Then you can create a reference to the WordprocessingCommentsPart part of the document.

    // To get the contents of a document part.
    public static string GetCommentsFromDocument(string document)
    {
        string comments = null;

        using (WordprocessingDocument wordDoc = WordprocessingDocument.Open(document, true))
        {
            MainDocumentPart mainPart = wordDoc.MainDocumentPart;
            WordprocessingCommentsPart WordprocessingCommentsPart = mainPart.WordprocessingCommentsPart;

You can then use a StreamReader object to read the contents of the WordprocessingCommentsPart part of the document and return its contents.

    using (StreamReader streamReader = new StreamReader(WordprocessingCommentsPart.GetStream()))
            {
                comments = streamReader.ReadToEnd();
            }
        }
        return comments;

Sample Code

The following code retrieves the contents of a WordprocessingCommentsPart part contained in a WordProcessing document package. You can run the program by calling the GetCommentsFromDocument method as shown in the following example.

    string document = @"C:\Users\Public\Documents\MyPkg5.docx";
    GetCommentsFromDocument(document);

Following is the complete code example in both C# and Visual Basic.


using DocumentFormat.OpenXml.Packaging;
using System;
using System.IO;

GetCommentsFromDocument(args[0]);

// To get the contents of a document part.
static string GetCommentsFromDocument(string document)
{
    string? comments = null;

    using (WordprocessingDocument wordDoc = WordprocessingDocument.Open(document, false))
    {
        if (wordDoc is null)
        {
            throw new ArgumentNullException(nameof(wordDoc));
        }

        MainDocumentPart mainPart = wordDoc.MainDocumentPart ?? wordDoc.AddMainDocumentPart();
        WordprocessingCommentsPart WordprocessingCommentsPart = mainPart.WordprocessingCommentsPart ?? mainPart.AddNewPart<WordprocessingCommentsPart>();

        using (StreamReader streamReader = new StreamReader(WordprocessingCommentsPart.GetStream()))
        {
            comments = streamReader.ReadToEnd();
        }
    }

    return comments;
}

See also

Open XML SDK class library reference