[Overview][Constants][Types][Classes][Procedures and functions][Variables][Index] | Reference for unit 'Forms' (#lcl)

# TApplicationHandlerType

Types of Application notification handlers.

## Declaration

Source position: forms.pp line 1380

`type TApplicationHandlerType = (`
`ahtIdle,` |  | Application becoming idle.
`ahtIdleEnd,` |  | Application idle state is ending.
`ahtKeyDownBefore,` |  | Handler for KeyDown events, invoked before interface and LCL handlers.
`ahtKeyDownAfter,` |  | Default handler for KeyDown events, invoked after interface and LCL handlers.
`ahtActivate,` |  | Handler invoked on application activated.
`ahtDeactivate,` |  | Handler invoked on application deactivated.
`ahtUserInput,` |  | Handler invoked on user input.
`ahtException,` |  | Handler invoked on handled exception.
`ahtEndSession,` |  | Handler invoked on session end.
`ahtQueryEndSession,` |  | Handler invoked before session ends.
`ahtMinimize,` |  | Handler invoked when the application is minimized.
`ahtModalBegin,` |  | Handler invoked when a form is shown modally.
`ahtModalEnd,` |  | Handler invoked when the last modal form is closed.
`ahtRestore,` |  | Handler invoked on application restored (from minimized state).
`ahtDropFiles,` |  | Handler invoked on files dropped.
`ahtHelp,` |  | Handler invoked on F1 key (help request).
`ahtHint,` |  | Handler invoked on Hint request.
`ahtShowHint,` |  | Handler invoked on Hint becoming visible.
`ahtGetMainFormHandle,` |  | Handler provides the Handle for the main form.
`ahtActionExecute,` |  | Handler signalled to execute an action.
`ahtActionUpdate` |  | Handler signalled to update an action.
`);`

## Description

TApplicationHandlerType is an enumerated type with values that identify handler categories used in TApplication.

TApplicationHandlerType is used as an index value for the internal array of TMethodList instances used in TApplication. It is passed as an argument to the AddHandler and RemoveHandler methods in TApplication to identify the method list where the handler is stored. It is also used in the implementation of TApplication methods used to retrieve, execute, or maintain handlers such as: Destroy and RemoveAllHandlersOfObject.