Read/Write 'Extended' file properties (C#)

Question

I'm trying to find out how to read/write to the extended file properties in C# e.g. Comment, Bit Rate, Date Accessed, Category etc that you can see in Windows explorer. Any ideas how to do this? EDIT: I'll mainly be reading/writing to video files (AVI/DIVX/...)

Answer 1

• After looking at a number of solutions on this thread and elsewhere the following code was put together. This is only to read a property.
• I could not get the Shell32.FolderItem2.ExtendedProperty function to work, it is supposed to take a string value and return the correct value and type for that property... this was always null for me and developer reference resources were very thin.
• The WindowsApiCodePack seems to have been abandoned by Microsoft which brings us the code below.

Use:

string propertyValue = GetExtendedFileProperty("c:\\temp\\FileNameYouWant.ext","PropertyYouWant");

1. Will return you the value of the extended property you want as a string for the given file and property name.
2. Only loops until it found the specified property - not until all properties are discovered like some sample code

3. Will work on Windows versions like Windows server 2008 where you will get the error "Unable to cast COM object of type 'System.__ComObject' to interface type 'Shell32.Shell'" if just trying to create the Shell32 Object normally.

   public static string GetExtendedFileProperty(string filePath, string propertyName)
   {
       string value = string.Empty;
       string baseFolder = Path.GetDirectoryName(filePath);
       string fileName = Path.GetFileName(filePath);
   
       //Method to load and execute the Shell object for Windows server 8 environment otherwise you get "Unable to cast COM object of type 'System.__ComObject' to interface type 'Shell32.Shell'"
       Type shellAppType = Type.GetTypeFromProgID("Shell.Application");
       Object shell = Activator.CreateInstance(shellAppType);
       Shell32.Folder shellFolder = (Shell32.Folder)shellAppType.InvokeMember("NameSpace", System.Reflection.BindingFlags.InvokeMethod, null, shell, new object[] { baseFolder });
   
       //Parsename will find the specific file I'm looking for in the Shell32.Folder object
       Shell32.FolderItem folderitem = shellFolder.ParseName(fileName);
       if (folderitem != null)
       {
           for (int i = 0; i < short.MaxValue; i++)
           {
               //Get the property name for property index i
               string property = shellFolder.GetDetailsOf(null, i);
   
               //Will be empty when all possible properties has been looped through, break out of loop
               if (String.IsNullOrEmpty(property)) break;
   
               //Skip to next property if this is not the specified property
               if (property != propertyName) continue;    
   
               //Read value of property
               value = shellFolder.GetDetailsOf(folderitem, i);
           }
       }
       //returns string.Empty if no value was found for the specified property
       return value;
   }
   

Answer 2

GetDetailsOf() Method - Retrieves details about an item in a folder. For example, its size, type, or the time of its last modification. File Properties may vary based on the Windows-OS version.

List<string> arrHeaders = new List<string>();

 Shell shell = new ShellClass();
 Folder rFolder = shell.NameSpace(_rootPath);
 FolderItem rFiles = rFolder.ParseName(filename);

 for (int i = 0; i < short.MaxValue; i++)
 {
      string value = rFolder.GetDetailsOf(rFiles, i).Trim();
      arrHeaders.Add(value);
 }

Answer 3

Solution 2016

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: MSDN: Implementing Property Handlers

Answer 4

Jerker's answer is little simpler. Here's sample code which works from MS:

var folder = new Shell().NameSpace(folderPath);
foreach (FolderItem2 item in folder.Items())
{
    var company = item.ExtendedProperty("Company");
    var author = item.ExtendedProperty("Author");
    // Etc.
}

For those who can't reference shell32 statically, you can invoke it dynamically like this:

var shellAppType = Type.GetTypeFromProgID("Shell.Application");
dynamic shellApp = Activator.CreateInstance(shellAppType);
var folder = shellApp.NameSpace(folderPath);
foreach (var item in folder.Items())
{
    var company = item.ExtendedProperty("Company");
    var author = item.ExtendedProperty("Author");
    // Etc.
}

Answer 5

For those of not crazy about VB, here it is in c#:

Note, you have to add a reference to Microsoft Shell Controls and Automation from the COM tab of the References dialog.

public static void Main(string[] args)
{
    List<string> arrHeaders = new List<string>();

    Shell32.Shell shell = new Shell32.Shell();
    Shell32.Folder objFolder;

    objFolder = shell.NameSpace(@"C:\temp\testprop");

    for( int i = 0; i < short.MaxValue; i++ )
    {
        string header = objFolder.GetDetailsOf(null, i);
        if (String.IsNullOrEmpty(header))
            break;
        arrHeaders.Add(header);
    }

    foreach(Shell32.FolderItem2 item in objFolder.Items())
    {
        for (int i = 0; i < arrHeaders.Count; i++)
        {
            Console.WriteLine(
              $"{i}\t{arrHeaders[i]}: {objFolder.GetDetailsOf(item, i)}");
        }
    }
}

Answer 6

There's a CodeProject article for an ID3 reader. And a thread at kixtart.org that has more information for other properties. Basically, you need to call the GetDetailsOf() method on the folder shell object for shell32.dll.