CreateWnd is called automatically when the tree view is first created or when the window must be destroyed and recreated to reflect property changes. 

CreateWnd first calls the CreateParams method to initialize the window-creation parameters, then calls CreateWindowHandle to create the window for the control. If the tree view's window was temporarily destroyed and recreated, CreateWnd reads various property settings from an in-memory cache where they were stored while there was no window. CreateWnd then sends a series of Windows messages to the newly-created tree view control to initialize its property settings. 

CreateParams 

CreateWindowHandle 

Perform 

DestroyWnd