Here is a great little article from Ashok kancheti on the sequence of methods on Forms in AX2012
This gives the information of method calls in the form level while
1. Opening the Form.
2. Creating/Updating/Deleting the record in the Form.
3. Closing the Form.
1. Sequence of Methods calls while opening the Form
Form — init ()
Form — Datasource — init ()
Form — run ()
Form — Datasource — execute Query ()
Form — Datasource — active ()
Sequence of Methods calls while closing the Form
Form — canClose ()
Form — close ()
2.1 Sequence of Methods calls while creating the record in the Form
Form — Datasource — create ()
Form — Datasource — initValue ()
Table — initValue ()
Form — Datasource — active ()
2.2 Sequence of Method calls while saving the record in the Form
Form — Datasource — ValidateWrite ()
Table — ValidateWrite ()
Form — Datasource — write ()
Table — insert ()
2.3 Sequence of Method calls while deleting the record in the Form
Form — Datasource — validatedelete ()
Table — validatedelete ()
Table — delete ()
Form — Datasource — active ()
3. Sequence of Methods calls while modifying the fields in the Form
Table — validateField ()
Table — modifiedField ()
Microsoft Dynamics AX: Sequence of calling form methods in AX 2012