Form extensions in D365FO

Source:  Customize through extension and overlayering - Finance & Operations | Dynamics 365 | Microsoft Docs

You can extend the functionality of a form by extending its controls and data sources. For example, in a form extension, you can:

• Add a new control.
• Enable or disable a control.
• Change the text or label property of a control.
• Change a control's visibility.
• Change a form's help text.
• Change a form's caption.
• Add a new data source.
• Add a form part.

Other ways to customize a form, such as reordering controls in the form are planned to be included in a future release. In Microsoft Dynamics AX 2012, you could override form methods. In the current version, you use extensions to implement event handlers that are called from the base implementations of form methods. The following table lists each method and its associated events.

FORM EXTENSIONS

Published form DataSource method	Preceding event	Succeeding event
active	N/A	Activated
delete	Deleting	Deleted
validateWrite	ValidatingWriting	ValidatedWrite
write	Writing	Written
create	Creating	Created
executeQuery	N/A	QueryExecuted
linkActive	N/A	PostLinkActive
init	N/A	Initialized
validateDelete	ValidatingDelete	ValidatedDelete
reread	N/A	Reread
selectionChanged	N/A	SelectionChanged
markChanged	N/A	MarkChanged
leaveRecord	LeavingRecord	LeftRecord

FORM EXTENSIONS

Published form Object method	Preceding event	Succeeding event
init	Initializing	Initialized
close	Closing	N/A
run	N/A	PostRun
activate	N/A	Activated

TABLE 3

Published form Control method	Preceding event	Succeeding event
modified	N/A	Modified
validate	Validating	Validated
leave	Leaving	LostFocus
enter	N/A	Enter
gotFocus	N/A	GotFocus
clicked	N/A	Clicked
selectionChange	SelectionChanging	N/A
pageActivated	N/A	PageActivated
allowPageDeactivate	AllowPageDeactivate	N/A
expand	Expanding	Expanded
tabChanged	N/A	TabChanged
dialogClosed	N/A	DialogClosed