How to extract text from a Microsoft Word document in C#

Earlier this week, I had cause to extract the text from a Microsoft Word document. Some naughty people had decided that the best way to export a CSV file from their application, was to save it as text in a .doc file. May my dog have mercy on their sole!

One could approach this problem in a nice complicated way, using IFilter for example, but I’ve taken the brave decision to assume that someone using software that exports Word documents will have a copy of Word to hand (risky!). This allows the much simpler solution of using Interop.

The first step is to add Microsoft.Office.Interop.Word to project references.

We don’t want that nasty Interop stuff leaking all over the place, so I’ve created a nice simple little class that hides it away with a nicer interface. Notice, I’ve made the class implement IDisposable, so that we can encapsulate the whole usage of Word in a using block; making the scope completely obvious.

using Microsoft.Office.Interop.Word;

public class WordApplication : IDisposable
{
    private readonly Application _application;
    private Document _document;

    public WordApplication()
    {
        _application = new ApplicationClass();
    }

    public void Open(string docFilename)
    {
        object docFilenameAsObject = docFilename;
        _document = _application.Documents.Open(ref docFilenameAsObject);
    }

    public void SaveAsText(string outputTxtFilename)
    {
        object outputTxtFilenameAsObject = outputTxtFilename;
        object formatAsObject = WdSaveFormat.wdFormatText;
        _document.SaveAs(ref outputTxtFilenameAsObject, ref formatAsObject);
    }

    public void Dispose()
    {
        _application.Application.Quit();
    }
}

This leaves us with a much nicer API to work with. We can now simply create a new .txt file from the old .doc as follows.

public static void ConvertDocToTxt(string docFilename, string txtFilename)
{
    using (var application = new WordApplication())
    {
       application.Open(docFilename);
       application.SaveAsText(txtFilename);
    }
}

Obviously, wrapping that in a try/catch block or similar, with appropriate exception handling would be the way forward. In real life one would also most likely introduce some interface to allow mocking, etc.

To conclude:

Pros

• Simple
• Short
• Supports both .doc and .docx (and probably other formats too)

Cons

• Requires Word
• Slow

Exercise for the reader: now you can all go away and write a little app to add to a right-click menu item in explorer to convert Word docs to text.