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

# TUpDown

[Properties (by Name)] [Methods (by Name)] [Events (by Name)]

TUpDown - a pair of arrow-like buttons which are used to increment or decrement some controlled variable; often attached to a scroll-bar, but can also control a digital numeric display

## Declaration

Source position: comctrls.pp line 1451

`type TUpDown = class(TCustomUpDown)`
`published`
`property AlignButton;` |  | AlignButton - how to align the button: left or right
`property Anchors;` |  | The set of anchor definitions for this control
`property Associate;` |  | Associate - the associated control whose properties (controlled variable) are to be changed by the UpDown control
`property ArrowKeys;` |  | ArrowKeys - if True, the control can be operated by the keyboard's arrow keys, which would simulate a click on the Next or Previous button
`property BorderSpacing;` |  | Determines the border spacing for this control
`property Enabled;` |  | Whether the control is Enabled (read/write). If not, it usually appears 'greyed-out'
`property Hint;` |  | Hint - a small informative pop-up box that appears when the mouse 'hovers' over a control
`property Min;` |  | Min - least value of controlled variable
`property Max;` |  | Max - greatest value of controlled variable
`property Increment;` |  | The amount by which the controlled variable is to be increased or decreased on each click
`property Constraints;` |  | Determine Constraints (max and min height and width) for this control
`property Orientation;` |  | Whether horizontal or vertical
`property ParentShowHint;` |  | ParentShowHint - does the control adopt the same hinting behaviour as its parent? Default is true
`property PopupMenu;` |  | PopupMenu - a context-sensitive menu that pops up when the right mouse button is clicked over this control
`property Position;` |  | The Position of the UpDown control
`property ShowHint;` |  | Flag to determine: Is hint to be displayed for this control?
`property TabOrder;` |  | The place this control occupies in the list of tabs
`property TabStop;` |  | Is the control in the sequence of controls accessed by successive presses of the Tab key?
`property Thousands;` |  | If True, multiply all displayed values and the Increment by 1000
`property Visible;` |  | Visible - can the control be seen?
`property Wrap;` |  | If True, displayed control or value starts again from minimum or maximum value if clicking a button would cause incrementing or decrmenting beyond the extreme value
`property OnChanging;` |  | OnChanging - event handler for a change in the value of the controlled variable
`property OnClick;` |  | OnClick - special event handler for a click on up or down button
`property OnContextPopup;` |  | Event handler to supply information when a context-sensitive pop-up menu is required
`property OnEnter;` |  | OnEnter - event handler for when the mouse enters the control, and the control receives focus
`property OnExit;` |  | OnExit - event handler for when the mouse leaves the control and it loses focus
`property OnMouseDown;` |  | Event handler for when a mouse button is pressed down
`property OnMouseEnter;`
`property OnMouseLeave;`
`property OnMouseMove;` |  | Event handler for mouse movement within the current control
`property OnMouseUp;` |  | Event handler for when the mouse button is released, ie "up"
`end;`

## Inheritance

`TUpDown` |  | TUpDown - a pair of arrow-like buttons which are used to increment or decrement some controlled variable; often attached to a scroll-bar, but can also control a digital numeric display
`TCustomUpDown` |  | TCustomUpDown - base class for TUpDown - a pair of arrow-like buttons which are used to increment or decrement some controlled variable; often attached to a scroll-bar, but can also control a digital numeric display
`TCustomControl` |  | TCustomControl - a base class for many window controls
`TWinControl`
`TControl`
`TLCLComponent` |  | TLCLComponent - base class for LCL components
`TComponent,IUnknown,IInterfaceComponentReference`
`TPersistent`
`TObject`

## Description

TUpDown - a pair of arrow-like buttons which are used to increment or decrement some controlled variable; often attached to a scroll-bar, but can also control a digital numeric display

The control definition itself does not specify the variable upon which the buttons operate. The application programmer is responsible for supplying an event handler for OnClick to determine which button has been selected (designated btNext or btPrev) and incrementing or decrementing the variable in the control with which the UpDown is associated.

The amount by which the variable is changed is set by the integer property Increment with the optional multiplier Thousands (a boolean property).

For example the UpDown control may be used to move a slider up and down a scale by a specified amount for each click; alternatively, a number may be displayed in a text box, and clicking the buttons of the UpDown control may increment or decrement the number displayed by a specified amount.

The latest version of this document can be found at lazarus-ccr.sourceforge.net .