ScrollEvent Class

Provide information about a ScrollEvent, generated when a scroll bar is manipulated.

Inheritance Hierarchy

Object
  Event
    ScrollEvent
      SliderEvent

Namespace: VO
Assembly: VOGUIClasses (in VOGUIClasses.dll) Version: 2.21

Syntax

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 CLASS ScrollEvent INHERIT Event

public class ScrollEvent : Event

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The ScrollEvent type exposes the following members.

Constructors

	Name	Description
	ScrollEvent	Initializes a new instance of the ScrollEvent class

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Properties

	Name	Description
	Handle	The pointer to the window where the event occurred (Inherited from Event.)
	IsWindowScroll	A logical value indicating whether the scroll bar which generated this ScrollEvent was a window scroll bar or a free-standing scroll bar.
	Message	A dword representing the Windows API message associated with the given event. (Inherited from Event.)
	OldPosition	A numeric value representing the old position of the thumb in a scroll bar when this ScrollEvent occurred (that is, where the thumb was located before being manipulated by the user).
	Position	A numeric value representing the desired position of the thumb in a scroll bar when this ScrollEvent occurred (that is, where the user has newly positioned the thumb).
	ScrollBar	The scroll bar that generated this ScrollEvent.
	ScrollBarID	The ID of the scroll bar that generated this ScrollEvent.
	TYPE	A string representing the type of scrolling action that took place when this ScrollEvent occurred.
	Window	An object indicating the window or control in which the event occurred. This is helpful, for example, for distinguishing between similar menu events coming from the same context menu attached to different controls. (Inherited from Event.)

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Fields

	Name	Description
	hWnd	(Inherited from Event.)
	lParam	(Inherited from Event.)
	oWindow	(Inherited from Event.)
	uMsg	(Inherited from Event.)
	wParam	(Inherited from Event.)

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Remarks

ScrollEvent events go to either Window:VerticalScroll() or Window:HorizontalScroll(), depending on whether a vertical or horizontal scroll bar generated the event. A ScrollEvent reports the following: what scroll bar caused the event, what type of scroll movement is requested, and whether the scroll bar is a window or a free-standing scroll bar. It also reports the old scroll bar position and the desired position. The old position is where the thumb was located before being manipulated by the user; the desired position is where the user has newly positioned the thumb (if the thumb is manipulated directly or calculated from the block and unit sizes).

Examples

Normally, when you receive a ScrollEvent, you would update the scroll bar's thumb position with code similar to the following:

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1aScrollEvt:ScrollBar:ThumbPosition := aScrollEvt:Position

Reference

VO Namespace