How to set extended file properties?

Question

I need to set the Company field value for some Word/PDF documents. I am talking about the extended file properties (summary/author/title, etc.) you see under File Properties.

I know how to get them (by using shell32.dll class library). I assumed that I could also set them with the same class library, but it seems like writing extended properties is a little bit more difficult and shell32.dll doesn't allow that.

I found something about taglib-sharp, which seems to have an option to set extended properties, but I don't really understand how it works.

Answer 1

Add following NuGet packages to your project:

• Microsoft.WindowsAPICodePack-Shell by Microsoft
• Microsoft.WindowsAPICodePack-Core by Microsoft

Read and Write Properties

using Microsoft.WindowsAPICodePack.Shell;
using Microsoft.WindowsAPICodePack.Shell.PropertySystem;

string filePath = @"C:\temp\example.docx";
var file = ShellFile.FromFilePath(filePath);

// Read and Write:

string[] oldAuthors = file.Properties.System.Author.Value;
string oldTitle = file.Properties.System.Title.Value;

file.Properties.System.Author.Value = new string[] { "Author #1", "Author #2" };
file.Properties.System.Title.Value = "Example Title";

// Alternate way to Write:

ShellPropertyWriter propertyWriter =  file.Properties.GetPropertyWriter();
propertyWriter.WriteProperty(SystemProperties.System.Author, new string[] { "Author" });
propertyWriter.Close();

Important:

The file must be a valid one, created by the specific assigned software. Every file type has specific extended file properties and not all of them are writable.

If you right-click a file on desktop and cannot edit a property, you wont be able to edit it in code too.

Example:

• Create txt file on desktop, rename its extension to docx. You can't edit its Author or Title property.
• Open it with Word, edit and save it. Now you can.

So just make sure to use some try catch

Further Topic: MS Docs: Implementing Property Handlers

Answer 2

Ok here is answer to my own question, since I wasn't really able to find my answer in this forum, it could be useful for others. Solution is to use dsofile.dll and OleDocumentPropertiesClass. Here is MS article about dsofile.dll - Link In this link, you can download dsofile.dll with some other files. But most probably, just like I did, you will face some weird problems that are hard to find a solution for.

1) After intalling dsofile.dll, you will need to register the class: oped cmd and navigate to c:\dsofile of to directory, where you have extracted your downloaded dsofile.dll. After that - write line regsvr32 dsofile.dll. You should get a messagebox saying that registeration was succesful. If not, most propably you don't have admin rights. You are going to need admin rights in case you want this to work.

2) After trying to use this class in your program, if you are using .NET 4.0 it is possible, that you will see error saying something like "class cannot be embedded ..." Well, for that, right click on dsofile in references list, properties -> embed interop files -> set to FALSE.

3) How to use:

    //creates new class of oledocumentproperties
    var doc = new OleDocumentPropertiesClass();

    //open your selected file
    doc.Open(pathToFile, false, dsoFileOpenOptions.dsoOptionDefault);

    //you can set properties with summaryproperties.nameOfProperty = value; for example
    doc.SummaryProperties.Company = "lol";
    doc.SummaryProperties.Author = "me";

    //after making changes, you need to use this line to save them
    doc.Save();

Answer 3

Windows Explorer (using shell32.dll) is able to display the extended properties because it understands a lot of different file formats and can parse these. However, to set an extended property you probably need a file format specific library. E.g. to set the author of an MP3 file file is very different compared to setting the author of an Office document. (Actually Windows Explorer allows you to set some extended properties on Office documents.)

The taglib-sharp only works with media files and is most likely not able to set extended properties of any other type of file.

What you need is a library or a tool you can automate to modify PDF files. You can try to google pdf sdk. If you also need to work with Word files you can use COM automation to automate Word. Depending on the Word file format used you may also be able to work directly with the file without having Word installed (XML being much easier than the old binary "streams" format).

Answer 4

To set properties, you could utilize Windows' Property System. It provides an interface for accessing the "Property Store Cache" (IPropertyStore) where you can read/set any file's properties (regardless of the format), and add your own custom properties (the c library propkey.h has a comprehensive list of all available properties; you can also find these using prop.exe). This is essentially creating a Property Handler that must be later registered to your file extension. It is officially unsupported in managed code, so you might either want to write your own wrapper or use c++ (since this is a c# tagged question).

If you're specifically asking for media properties, check out metadata handlers, which are essentially codecs that extract your properties from the file and also called by explorer by default if you register them correctly.