RequestUpdateUI (Function)

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"Request for refreshing the display" event
"Presenter" attribute

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RequestUpdateUI (Function)

In french: DemandeMiseAJourIHM

Warning
From version 25, this function is kept for backward compatibility. It is recommended to use RequestRefreshUI.

Requests the execution of the "Request for refreshing the display" event (and gives back control without waiting for the execution of the event).

Remarks:

The "Request for refreshing the display" event is available for windows, internal windows, pages, internal pages, control templates and supercontrols.
If this function is called multiple times, all subsequent calls with the same parameters as calls that have not yet been executed are ignored.
If the function is called in main the thread, the "Request for refreshing the display" event will be executed after the current process.
If the function is called in a secondary thread, the "Request for refreshing the display" event will be executed when the window is refreshed.

Uses: This function is used in particular:

when refreshing the interface via threads.
when using MVP (Model - View - Presenter) programming. For more details, see MVP Presentation: Model - View - Presenter.

Example

// Traitement d'enregistrement
// L'interface graphique devra être mise à jour 
DemandeMiseAJourIHM()

// ----------------------------------------------------------------
// -- Evénement Demande de mise à jour de l'affichage de FEN_Fiche_Contact
// Mise à jour du titre de la fenêtre
MySelf..Title = gpclFicheContact.p_sNomComplet

// Mise à jour des champs liés de la fenêtre
SourceToScreen()

Syntax

RequestUpdateUI([<Parameter 1> [... [, <Parameter N>]]])

<Parameter 1>: Optional parameter corresponding to the type expected by the "Request for refreshing the display" event

First parameter that will be passed to the "Request for refreshing the display" window event.

<Parameter N>: Type of value expected by the "Request for refreshing the display" event

Nth parameter that will be passed to the "Request for refreshing the display" window event.

Remarks

"Request for refreshing the display" event

One of the events associated with the window is "Request for refreshing the display". This event groups together the update code for the window's fields: field content, status (visible, grayed, etc.), label to be updated, etc.

This event can receive parameters. Simply declare a procedure in the event. For example:

// Request for refreshing the display
PROCEDURE AskForRefresh(RefreshType is boolean)

This event is started upon request by the following functions:

RequestUpdateUI: Executes the "Display update request" event at the end of current processing (asynchronous launch)..
ExecuteUpdateUI: Immediately executes the "Request for refreshing the display" event.
RequestUpdateUIParent: Executes the "Request for refreshing the display" event of the higher level at the end of the current process (asynchronous execution).
ExecuteUpdateUIParent: Immediately executes the "Request for refreshing the display" event of the higher level. When these functions are called, you can specify the value of the parameters expected by "Request for refreshing the display".
Note: The element whose "Display update request" event is executed depends on the code from which the RequestUpdateUI function has been called.. If it is a class with the presenter attribute, the element will be the window associated with the class. Otherwise, it will be the element from which the code was executed.

"Presenter" attribute

The presenter attribute is used to associate a class of the presenter layer with a view (window, page or report).

This attribute is mainly used in the global declaration of the windows generated by the MVP RAD in WINDEV.

For example:

PROCEDURE WIN_Table_MyExampleFile(...
	gclPresenter is PTableMyExampleFile dynamic<presenter>=Null)

With this attribute, the "Request for refreshing the display" window event will be triggered by:

any call to RequestUpdateUI from a class declared as <presenter>,
any call from any class associated with the <presenter> class.

For more details, see RAD MVP: "presentation" attribute.

Business / UI classification: Neutral code

Component: wd300vm.dll