Hi Veselin Vasilev
Thanks for your quick reply.
In order to fully understand what you have said I will try to re-elaborate it.
The nodes can not be displayed because the ParentId is NOT NULL right?
I need to set my ParentId as NULL in order for me to set it as the main node right?
I have updated my project to show you that even if my ParentId is NOT NULL, I can still see it by using an Empty GUID value.
Does it have any special functionality when it detects the type of GUID on the Treeview?
The problem is, I need to retrieve a specific records then I will display it in Treeview. If the ParentId of an item is not included in the list, it should be created as a main node.