TScrollBox class

In unit Forms

Implements a windowed control with scroll bars.

Declaration

pascal

TScrollBox = class(TScrollingWinControl)

Inheritance

Description

TScrollBox is a TScrollingWinControl descendant that implements a windowed control with scroll bars. It uses the logical and physical display areas introduced in the ancestor class, and allows a scrollable area to be displayed on a form or panel. The logical (or virtual) client area represents the dimensions needed for the child Controls added to the class instance. When the logical display area is larger than the visible area for the control, scroll bars allow the content to be moved into the visible area for the control.

TScrollBox sets the visibility for properties inherited from the ancestor class. TScrollBox includes an overridden constructor which sets the default values for properties in the class instance.

Child Controls can be added to the class instance at design-time, or at run-time by setting the scroll box as the Parent for a control.

The AutoScroll property indicates whether the scroll bars are automatically displayed (or hidden) as needed when the control is resized, or when child Controls are updated. This includes setting the page, range, and visibility for the scroll bars. Use the HorzScrollBar and VertScrollBar properties to access scroll bar page, range, and visibility when AutoScroll is not enabled.

An example application using TScrollBox is located in the examples/imgviewer directory.

Properties

`Align`	published	Specifies the placement of the control on its Parent control.
`Anchors`	published	The set of anchor definitions for this control.
`AutoSize`	published	Allows automatic adjustment of the size for the control, according to its content.
`AutoScroll`	published	Indicates whether scroll bars are automatically displayed or hidden when needed.
`BorderSpacing`	published	Determines the inner and outer border spacing for this control.
`BiDiMode`	published	Indicates whether text controls use in bi-directional reading.
`BorderStyle`	published	Line style used to draw the border around the control.
`ChildSizing`	published	Provides a grid (table) layout for the children of this control.
`ClientHeight`	published	The height for the client area on the control.
`ClientWidth`	published	The width of the client area for the control.
`Constraints`	published	Contains the minimum and maximum Width and Height for the control.
`DockSite`	published	Allows controls to be drag-and-dock-ed into this control.
`DragCursor`	published	The cursor shape shown during a drag operation.
`DragKind`	published	Indicates the action performed for a drag operation: drag-and-drop or drag-and-dock.
`DragMode`	published	Determines how a drag operation is started for the control.
`Enabled`	published	Determines whether the control responds to mouse or keyboard input.
`Color`	published	The background color for the control.
`Font`	published	The font to be used for text display in this control.
`ParentBackground`	published	Indicates if the control uses the background from its Parent control.
`ParentBiDiMode`	published	Indicates whether the BiDiMode settings in the Parent control are used.
`ParentColor`	published	Use the Color from the Parent control, when enabled.
`ParentFont`	published	Indicates if the Font from the Parent control is used in the control.
`ParentShowHint`	published	If True, the value of ShowHint for the control will be the same as the one from the Parent. Default is True.
`PopupMenu`	published	A context-sensitive menu that pops up when the right mouse button is clicked over this control.
`ShowHint`	published	Enables Hint display for the control.
`TabOrder`	published	Indicates the navigation order for the control when the user presses the Tab or Shift+Tab key.
`TabStop`	published	Allows the user to navigate to / from the control by pressing the Tab or Shift+Tab keys.
`Visible`	published	Allows the control, and all of its children, to be displayed or hidden.

Methods

`WSRegisterClass`	protected	Registers this component class with the current WidgetSet.
`SetParentBackground`	protected	Sets the value for the ParentBackground property.
`CMParentColorChanged`	protected	Handles the CM_PARENTCOLORCHANGED message for the control.
`Loaded`	protected	Performs actions when a component has been loaded during LCL component streaming.
`UpdateParentColorChange`	protected	Updates ControlStyle flags to set the opacity for the control.
`Create`	public	Constructor for the class instance.

Events

`OnClick`	published	Notification handler for mouse clicks.
`OnConstrainedResize`	published	This handler can supply specific Constraints (size limits), when the control is resized.
`OnDblClick`	published	Event handler signalled when a mouse double click occurs in the control.
`OnDockDrop`	published	Event handler signalled for the drop of a control to be docked.
`OnDockOver`	published	Event handler signalled when a control is moved over a docksite; determines whether the drop event is accepted or rejected.
`OnDragDrop`	published	Event handler signalled when an object is dropped onto the control.
`OnDragOver`	published	Event handler signalled when a control is dragged over the control instance.
`OnEndDock`	published	Event handler signalled for the end of a drag-dock operation.
`OnEndDrag`	published	Event handler signalled for the end of a drag-drop operation.
`OnEnter`	published	Event handler signalled when the control receives focus.
`OnExit`	published	Event handler signalled when the control loses focus.
`OnGetSiteInfo`	published	Provides information about the DockSite for the control.
`OnMouseDown`	published	Event handler signalled when a mouse down event is handled for the control.
`OnMouseEnter`	published	Event handler signalled when the mouse pointer has entered the control.
`OnMouseLeave`	published	Event handler signalled when the mouse pointer has left the control.
`OnMouseMove`	published	Event handler signalled when the mouse pointer is moved in the control.
`OnMouseUp`	published	Event handler signalled when a mouse up event is handled for the control.
`OnMouseWheel`	published	Event handler for mouse wheel turned.
`OnMouseWheelDown`	published	Event handler signalled for a downward movement of the mouse wheel.
`OnMouseWheelUp`	published	Event handler signalled for an upward movement of the mouse wheel.
`OnMouseWheelHorz`	published	Event handler signalled for a horizontal movement of the mouse wheel.
`OnMouseWheelLeft`	published	Event handler signalled for a leftward movement of the mouse wheel.
`OnMouseWheelRight`	published	Event handler signalled for a rightward movement of the mouse wheel.
`OnResize`	published	Notification handler for a resize of the control.
`OnStartDock`	published	Event handler for the start of a docking operation.
`OnStartDrag`	published	Event handler signalled for the start of a dragging operation.
`OnUnDock`	published	Event handler signalled before a control is undocked from its DockSite.
`OnPaint`	published	Event handler signalled to paint the control.