Extract styles from a word processing document

  • Articolo

This topic shows how to use the classes in the Open XML SDK for Office to programmatically extract the styles or stylesWithEffects part from a word processing document to an XDocument instance. It contains an example ExtractStylesPart method to illustrate this task.

ExtractStylesPart Method

You can use the ExtractStylesPart sample method to retrieve an XDocument instance that contains the styles or stylesWithEffects part for a Microsoft Word 2010 or Microsoft Word 2013 document. Be aware that in a document created in Word 2010, there will only be a single styles part; Word 2013 adds a second stylesWithEffects part. To provide for "round-tripping" a document from Word 2013 to Word 2010 and back, Word 2013 maintains both the original styles part and the new styles part. (The Office Open XML File Formats specification requires that Microsoft Word ignore any parts that it does not recognize; Word 2010 does not notice the stylesWithEffects part that Word 2013 adds to the document.) You (and your application) must interpret the results of retrieving the styles or stylesWithEffects part.

The ExtractStylesPart procedure accepts a two parameters: the first parameter contains a string indicating the path of the file from which you want to extract styles, and the second indicates whether you want to retrieve the styles part, or the newer stylesWithEffects part (basically, you must call this procedure two times for Word 2013 documents, retrieving each the part). The procedure returns an XDocument instance that contains the complete styles or stylesWithEffects part that you requested, with all the style information for the document (or a null reference, if the part you requested does not exist).

    public static XDocument ExtractStylesPart(
      string fileName,
      bool getStylesWithEffectsPart = true)

The complete code listing for the method can be found in the Sample Code section.

Calling the Sample Method

To call the sample method, pass a string for the first parameter that contains the file name of the document from which to extract the styles, and a Boolean for the second parameter that specifies whether the type of part to retrieve is the styleWithEffects part (true), or the styles part (false). The following sample code shows an example. When you have the XDocument instance you can do what you want with it; in the following sample code the content of the XDocument instance is displayed to the console.

    string filename = @"C:\Users\Public\Documents\StylesFrom.docx";

    // Retrieve the StylesWithEffects part. You could pass false in the 
    // second parameter to retrieve the Styles part instead.
    var styles = ExtractStylesPart(filename, true);

    // If the part was retrieved, send the contents to the console.
    if (styles != null)
        Console.WriteLine(styles.ToString());

How the Code Works

The code starts by creating a variable named styles that the method returns before it exits.

    // Declare a variable to hold the XDocument.
    XDocument styles = null;
    // Code removed here...
    // Return the XDocument instance.
    return styles;

The code continues by opening the document by using the Open method and indicating that the document should be open for read-only access (the final false parameter). Given the open document, the code uses the MainDocumentPart property to navigate to the main document part, and then prepares a variable named stylesPart to hold a reference to the styles part.

    // Open the document for read access and get a reference.
    using (var document = 
        WordprocessingDocument.Open(fileName, false))
    {
        // Get a reference to the main document part.
        var docPart = document.MainDocumentPart;

        // Assign a reference to the appropriate part to the
        // stylesPart variable.
        StylesPart stylesPart = null;
        // Code removed here...
    }

Find the Correct Styles Part

The code next retrieves a reference to the requested styles part by using the getStylesWithEffectsPart Boolean parameter. Based on this value, the code retrieves a specific property of the docPart variable, and stores it in the stylesPart variable.

    if (getStylesWithEffectsPart)
        stylesPart = docPart.StylesWithEffectsPart;
    else
        stylesPart = docPart.StyleDefinitionsPart;

Retrieve the Part Contents

If the requested styles part exists, the code must return the contents of the part in an XDocument instance. Each part provides a GetStream method, which returns a Stream. The code passes the Stream instance to the XmlNodeReader.Create method, and then calls the XDocument.Load method, passing the XmlNodeReader as a parameter.

    // If the part exists, read it into the XDocument.
    if (stylesPart != null)
    {
        using (var reader = XmlNodeReader.Create(
          stylesPart.GetStream(FileMode.Open, FileAccess.Read)))
        {
            // Create the XDocument.
            styles = XDocument.Load(reader);
        }
    }

Sample Code

The following is the complete ExtractStylesPart code sample in C# and Visual Basic.

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

if (args is [{ } fileName, { } getStyleWithEffectsPart])
{
    ExtractStylesPart(fileName, getStyleWithEffectsPart);
}
else if (args is [{ } fileName2])
{
    ExtractStylesPart(fileName2);
}

// Extract the styles or stylesWithEffects part from a 
// word processing document as an XDocument instance.
static XDocument ExtractStylesPart(string fileName, string getStylesWithEffectsPart = "true")
{
    // Declare a variable to hold the XDocument.
    XDocument? styles = null;

    // Open the document for read access and get a reference.
    using (var document = WordprocessingDocument.Open(fileName, false))
    {
        if (document.MainDocumentPart is null || document.MainDocumentPart.StyleDefinitionsPart is null || document.MainDocumentPart.StylesWithEffectsPart is null)
        {
            throw new ArgumentNullException("MainDocumentPart and/or one or both of the Styles parts is null.");
        }

        // Get a reference to the main document part.
        var docPart = document.MainDocumentPart;

        // Assign a reference to the appropriate part to the
        // stylesPart variable.
        StylesPart? stylesPart = null;

        if (getStylesWithEffectsPart.ToLower() == "true")
            stylesPart = docPart.StylesWithEffectsPart;
        else
            stylesPart = docPart.StyleDefinitionsPart;

        using var reader = XmlNodeReader.Create(stylesPart.GetStream(FileMode.Open, FileAccess.Read));

        // Create the XDocument.
        styles = XDocument.Load(reader);
    }
    // Return the XDocument instance.
    return styles;
}

See also