Add status icons over file icons in Explorer, like Dropbox or SVN in .NET

Question

I'm writing a Windows service application in C# with FileSystemWatcher.

How can I add status icons to files and folders in Windows Explorer similar to how Dropbox or SVN do it?

Answer 1

For anyone still interessted in this question:

Here is a codeproject link which describes the process in great detail.

It uses the SharpShell library, which can also be found on nuget.

Code, from the codeproject, looks something like that:

[ComVisible(true)]
public class ReadOnlyFileIconOverlayHandler : SharpIconOverlayHandler
{
  protected override int GetPriority()
  {
    //  The read only icon overlay is very low priority.
    return 90;
  }

  protected override bool CanShowOverlay(string path, FILE_ATTRIBUTE attributes)
  {
    try
    {
      //  Get the file attributes.
      var fileAttributes = new FileInfo(path);

      //  Return true if the file is read only, meaning we'll show the overlay.
      return fileAttributes.IsReadOnly;
    }
    catch (Exception) { return false; }
  }

  protected override System.Drawing.Icon GetOverlayIcon()
  {
    //  Return the read only icon.
    return Properties.Resources.ReadOnly;
  }
}