WidgetGetUserData

Syntax

*UserData = WidgetGetUserData(Widget)

Description

Retrieves the user-defined data pointer associated with the specified widget.

Parameters

Return Value

Returns the pointer (*UserData) that was previously associated with the widget using WidgetSetUserData() or during creation with CreateWidget(). Returns #Null if no user data was set or if the widget handle is invalid.

Remarks

User data allows developers to attach arbitrary application-specific data (like pointers to structures or object instances) to a widget, often used within event handlers to access related information without relying on global variables.

Example

IncludeFile "ProGUI_PB.pbi"

StartProGUI()

Structure MyWidgetInfo
  ID.i
  Label$
EndStructure

; Event handler using UserData
Procedure WidgetInfoHandler(Widget, EventType, *EventData, *UserData)
  If EventType = #PG_Event_MouseLeftButtonDown
    *widgetUserData.MyWidgetInfo = WidgetGetUserData(Widget)
    If *widgetUserData ; Check if *widgetUserData is valid
        Debug "Widget Clicked!"
        Debug "ID: " + Str(*widgetUserData\ID)
        Debug "Label: " + *widgetUserData\Label$
    EndIf
  EndIf
EndProcedure

MyWindow = CreateWindow(0, 0, 300, 200, "User Data Example", #PG_Window_Default | #PG_Window_LayoutFlex)
RootLayout = WindowGetLayout(MyWindow)

If MyWindow
  ; Allocate memory for user data
  *Info1.MyWidgetInfo = AllocateStructure(MyWidgetInfo)
  *Info1\ID = 101
  *Info1\Label$ = "First Button"

  *Info2.MyWidgetInfo = AllocateStructure(MyWidgetInfo)
  *Info2\ID = 102
  *Info2\Label$ = "Second Button"

  ; Create widgets and set user data
  Widget1 = CreateWidget(0, 0, 100, 30, *Info1)
  WidgetSetClass(Widget1, "button")
  AddEventHandler(Widget1, #PG_Event_MouseLeftButtonDown, @WidgetInfoHandler())

  Widget2 = CreateWidget(0, 0, 100, 30)
  WidgetSetUserData(Widget2, *Info2) ; Set data after creation
  WidgetSetClass(Widget2, "button")
  AddEventHandler(Widget2, #PG_Event_MouseLeftButtonDown, @WidgetInfoHandler())

  ; Retrieve user data later
  *RetrievedInfo = WidgetGetUserData(Widget1)
  If *RetrievedInfo = *Info1
    Debug "Retrieved UserData for Widget1 matches."
  EndIf

  WindowShow(MyWindow, #True, #PG_Window_ScreenCentered)

  Repeat
    Event = WaitWindowEvent()
  Until Event = #PB_Event_CloseWindow

  ; Clean up allocated memory
  FreeStructure(*Info1)
  FreeStructure(*Info2)
EndIf

StopProGUI()

See Also

WidgetSetUserData, CreateWidget, AddEventHandler

Supported OS

Windows, Linux