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

# TCheckComboBox

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

Combo-box control which displays check boxes for the items in the control.

## Declaration

Source position: comboex.pas line 333

`type TCheckComboBox = class(TCustomCheckCombo)`
`published`
`property Align: TAlign;` |  | Specifies the placement of the control on its Parent control.
`property AllowGrayed: Boolean;` |  | Indicates if check boxes can be drawn in the indeterminate state.
`property Anchors: TAnchors;` |  | The set of anchor definitions for this control.
`property ArrowKeysTraverseList: Boolean;` |  | Indicates if keyboard Arrow (or cursor) keys can be used to move through the list.
`property AutoDropDown: Boolean;` |  | Makes the drop-down list appear as soon as the user starts entering text.
`property AutoSize: Boolean;` |  | Allows automatic adjustment of the size for the control, according to its content.
`property BidiMode: TBiDiMode;` |  | Indicates whether text controls use in bi-directional reading.
`property BorderSpacing: TControlBorderSpacing;` |  | Determines the inner and outer border spacing for this control.
`property BorderStyle: TBorderStyle;` |  | Indicates the border style displayed around the control.
`property Color: TColor;` |  | The background color for the control.
`property Constraints: TSizeConstraints;` |  | Contains the minimum and maximum Width and Height for the control.
`property Count: Integer;` |  | Reflects the number of check boxes defined for the control.
`property DragCursor: TCursor;` |  | The cursor shape shown during a drag operation.
`property DragKind: TDragKind;` |  | Indicates the action performed for a drag operation: drag-and-drop or drag-and-dock.
`property DragMode: TDragMode;` |  | Determines how a drag operation is started for the control.
`property DropDownCount: Integer;` |  | The maximum number of Items visible in the drop-down list for the control.
`property Enabled: Boolean;` |  | Determines whether the control responds to mouse or keyboard input.
`property Font: TFont;` |  | The font to be used for text display in this control.
`property ItemHeight: Integer;` |  | The default height of an item in the drop-down for the control.
`property ItemIndex: Integer;` |  | The index of the currently selected item, or -1 if no item is selected.
`property Items: TStrings;` |  | The list of items displayed in the combo-box control.
`property ItemWidth: Integer;` |  | The minimum width of the items in the drop-down list.
`property MaxLength: Integer;` |  | The maximum length for text entered in the edit box for the control.
`property ParentBidiMode: Boolean;` |  | Indicates whether the BiDiMode settings in the Parent control are used.
`property ParentColor: Boolean;` |  | Use the Color from the Parent control, when enabled.
`property ParentFont: Boolean;` |  | Indicates if the Font from the Parent control is used in the control.
`property ParentShowHint: Boolean;` |  | If True, the value of ShowHint for the control will be the same as the one from the Parent. Default is True.
`property PopupMenu: TPopupMenu;` |  | A context-sensitive menu that pops up when the right mouse button is clicked over this control.
`property ShowHint: Boolean;` |  | Enables Hint display for the control.
`property Sorted: Boolean;` |  | Determines whether the list entries are sorted in alphanumeric order.
`property TabOrder: TTabOrder;` |  | Indicates the navigation order for the control when the user presses the Tab or Shift+Tab key.
`property TabStop: Boolean;` |  | Allows the user to navigate to / from the control by pressing the Tab or Shift+Tab keys.
`property Text: TCaption;` |  | The value in the edit box for the control.
`property TextHint: TTranslateString;` |  | Default hint text shown when the Text property is empty for the control.
`property Visible: Boolean;` |  | Allows the control, and all of its children, to be displayed or hidden.
`property OnChange: TNotifyEvent;` |  | Event handler signalled for user changes to the text in the edit box.
`property OnChangeBounds: TNotifyEvent;` |  | Event handler signalled when the Bounds for the control have been changed.
`property OnClick: TNotifyEvent;` |  | Notification handler for mouse clicks.
`property OnCloseUp: TNotifyEvent;` |  | Handler invoked when the drop-down list closes.
`property OnContextPopup: TContextPopupEvent;` |  | Invoked when a context-sensitive pop-up menu is requested.
`property OnDblClick: TNotifyEvent;` |  | Event handler signalled when a mouse double click occurs in the control.
`property OnDragDrop: TDragDropEvent;` |  | Event handler signalled when an object is dropped onto the control.
`property OnDragOver: TDragOverEvent;` |  | Event handler signalled when a control is dragged over the control instance.
`property OnEndDrag: TEndDragEvent;` |  | Event handler signalled for the end of a drag-drop operation.
`property OnDropDown: TNotifyEvent;` |  | Handler invoked when the list has dropped down.
`property OnEditingDone: TNotifyEvent;` |  | Event handler signalled when editing is completed for the control.
`property OnEnter: TNotifyEvent;` |  | Event handler signalled when the control loses focus.
`property OnExit: TNotifyEvent;` |  | Event handler signalled when the control loses focus.
`property OnGetItems: TNotifyEvent;` |  | Handler invoked when widgetset items list can be populated.
`property OnItemChange: TCheckItemChange;` |  | Event handler signalled when the state for a check box in the control is changed.
`property OnKeyDown: TKeyEvent;` |  | Event handler signalled for key down keyboard events.
`property OnKeyPress: TKeyPressEvent;` |  | Event handler signalled for character data entered by the user.
`property OnKeyUp: TKeyEvent;` |  | Event handler signalled when a key up event has occurred for the control.
`property OnMouseDown: TMouseEvent;` |  | Event handler signalled when a mouse down event is handled for the control.
`property OnMouseEnter: TNotifyEvent;` |  | Event handler signalled when the mouse pointer has entered the control.
`property OnMouseLeave: TNotifyEvent;` |  | Event handler signalled when the mouse pointer has left the control.
`property OnMouseMove: TMouseMoveEvent;` |  | Event handler signalled when the mouse pointer is moved in the control.
`property OnMouseUp: TMouseEvent;` |  | Event handler signalled when a mouse up event is handled for the control.
`property OnMouseWheel: TMouseWheelEvent;` |  | Event handler for mouse wheel turned.
`property OnMouseWheelDown: TMouseWheelUpDownEvent;` |  | Event handler signalled for a downward movement of the mouse wheel.
`property OnMouseWheelUp: TMouseWheelUpDownEvent;` |  | Event handler signalled for an upward movement of the mouse wheel.
`property OnStartDrag: TStartDragEvent;` |  | Event handler signalled for the start of a dragging operation.
`property OnSelect: TNotifyEvent;` |  | Handler invoked when an item is selected.
`property OnUTF8KeyPress: TUTF8KeyPressEvent;` |  | Handler for a character entered by the user.
`end;`

## Inheritance

`TCheckComboBox` |  | Combo-box control which displays check boxes for the items in the control.
`TCustomCheckCombo` |  | Base class for a combo-box which displays check boxes for Items in the control.
`TCustomComboBox` |  | The base class for combo-box components.
`TWinControl` |  | Implements a windowed control which can contain other child controls.
`TControl` |  | The base class for visible controls.
`TLCLComponent` |  | The base class for LCL components which have an associated widget.
`TComponent`
?
`TObject`

## Description

TCheckComboBox is a TCustomCheckCombo descendant which implements a combo-box which displays check boxes for the Items in the control. It behaves like an ordinary combo-box with a drop-down using a customizable number of visible rows.

TCheckComboBox provides additional properties, methods, and events which allow the checked state for values in Items to be specified as either a Boolean or a TCheckBoxState value. An OnItemChange event handler is added to perform custom actions when the Checked value for an item is changed. Convenience methods are included which allow check boxes to be added or deleted, or toggle their value.

TCheckComboBox sets the visibility for property defined in ancestor classes.

## See also

TCustomCheckCombo |  | Base class for a combo-box which displays check boxes for Items in the control.