my.cs

private static void Folder_OnDrop(object sender, ShellFolderDropEventArgs e)
{
  e.AllowedEffects = Constants.DROP_EFFECT_COPY | Constants.DROP_EFFECT_MOVE | Constants.DROP_EFFECT_LINK;

  var formats = e.Formats.Split('\n');
  var format = formats[0];

  int count = 0;
  var data = folder.GetDragData(e.TaskId, format, 0, ref count);

  if (count > 0)
  {
    var str = Encoding.Unicode.GetString(data);
    Console.WriteLine($"Drop task id: " + e.TaskId + ",  target id = " + e.TargetId + ", key state = " + e.KeyState);

    var id = folder.PIDLToId(str);
    Console.WriteLine("  Drop PIDLToId: " + id);
    Console.WriteLine("  Formats: " + e.Formats);
  }
}

private static void Folder_OnDrag(object sender, ShellFolderDragEventArgs e)
{
  e.AllowedEffects = Constants.DROP_EFFECT_COPY | Constants.DROP_EFFECT_MOVE | Constants.DROP_EFFECT_LINK;

  var formats = e.Formats.Split('\n');
  var format = formats[0];

  int count = 0;
  var data = folder.GetDragData(e.TaskId, format, 0, ref count);

  if (count > 0)
  {
    var str = Encoding.Unicode.GetString(data);
    Console.WriteLine($"Drag task id: " + e.TaskId + ", target id = " + e.TargetId + ", key state = " + e.KeyState + ", drag type = " + e.DragType);

    var id = folder.PIDLToId(str);
    Console.WriteLine("  Drag PIDLToId: " + id);
    Console.WriteLine("  Formats: " + e.Formats);
  }
}