1. How to update Explorer views (ShellView and FolderView)?

  To update Explorer's views you must to use the following methods of DataProvider component:

•  NotifyAddGrain - used to notify about just created DataGrains
•  NotifyDeleteGrain - used to notify about deleted DataGrains
•  NotifyRenameGrain - used to notify about renamed DataGrains
•  NotifyUpdateGrain - used to notify about modified DataGrains

  Also the property ChangeNotifyType of ShellView component used to specify how the update should be performed. If its ChangeNotifyType=cntLocal it should use internal method of notifications, if ChangeNotifyType=cntGlobal it should use system-defined way to send notifications. In this case your NSE may be locked by Windows caching system and you will need to restart Windows Shell.

2. How to handle dropping folders into the Namespace Extension.

  Shell+ handles dropping of folders and subfolders automatically. It parses incoming shell data and raises appropriate DataProvider events: OnCreateNewFolder, OnNewGrainFromFileEx or OnNewGrainFromStreamEx. The last two events are interchangeable (OnNewGrainFromStreamEx event was introduced to support drag&drop from Outlook). So, to support dropping folders on your NSE you just need to handle OnCreateNewFolder event.

  In the OnCreateNewFolder event handler you should create folder object in your data storage and return the DataGrain which initialized with the data from newly created folder. Here is an example:

procedure TPermanentModule.DataProviderCreateNewFolder(
  Sender: TSxCustomProvider; OwnerFolderGrain: TSxCustomDataGrain;
  NewFolderName: WideString; out NewFolderGrain: TSxCustomDataGrain);
var
  tempFileStg:IMDFileObj;
  tempNewStg:IMDFileObj;
begin
  MDServer.GetRelativeFileStorage(OwnerFolderGrain.Strings.Values[vGrainPath],tempFileStg);
  if tempFileStg=nil then
     Exit;
  tempFileStg.AddNewChild(NewFolderName,tempNewStg);
  NewFolderGrain:=CreateGrainFromStg(tempNewStg,OwnerFolderGrain);
end;