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

TDBLookupListBox

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

Implements a data-aware listbox control with database lookup capabilities.

Declaration

Source position: dbctrls.pp line 454

type TDBLookupListBox = class(TCustomDBListBox)

protected

  procedure DataChange(); override;

  

Performs actions needed when a new DataField value is selected using the lookup dataset.

  procedure DoSelectionChange(); override;

  

Performs actions needed when the selected item in the listbox is changed.

  procedure InitializeWnd; override;

  

Initializes the window handle for the control.

  procedure DestroyWnd; override;

  

Frees the window handle and updates the address used for the Items in the controls.

  procedure KeyDown(); override;

  

Applies the specified virtual key code to the control.

  procedure Loaded; override;

  

Performs actions needed when the control has loaded using the LCL streaming mechanism.

  procedure UpdateData(); override;

  

Updates the data in the lookup dataset for the control.

  function IsUnbound;

  

Indicates if the control is being used in the "unbound" mode.

public

  constructor Create(); override;

  

Constructor for the class instance.

  property KeyValue: Variant; [rw]

  

Accesses the value for the KeyField in the lookup dataset.

published

  property Align: TAlign;

  

Specifies the placement of the control inside its Parent.

  property Anchors: TAnchors;

  

The set of anchor definitions for this control.

  property BiDiMode: TBiDiMode;

  

Customization (of text controls) in bidirectional reading environments.

  property BorderSpacing: TControlBorderSpacing;

  

Determines the inner and outer border spacing for this control.

  property BorderStyle: TBorderStyle;

  

Indicates if borders are displayed around the control.

  property Color: TColor;

  

The background color of the control.

  property Constraints: TSizeConstraints;

  

The minimum and maximum Width and Height for the control.

  property DataField: string;

  

Name for the field in the linked dataset used in the control.

  property DataSource: TDataSource;

  

Provides access to the linked dataset for the control.

  property DoubleBuffered: Boolean;

  

Allows to reduce flicker in the painting of the control.

  property DragCursor: TCursor;

  

The cursor shape shown while the control is dragged.

  property DragKind: TDragKind;

  

The operation when the control is dragged - Drag or Dock.

  property DragMode: TDragMode;

  

Allows the user to drag the control.

  property Enabled: Boolean;

  

Determines whether the control reacts on mouse or keyboard input.

  property Font: TFont;

  

The font to be used for text display in this control.

  property KeyField: string; [rw]

  

Field name in the lookup dataset with the value for the control.

  property ListField: string; [rw]

  

Field name with the descriptive value displayed in the listbox.

  property ListFieldIndex: Integer; [rw]

  

Ordinal position of the field in the lookup dataset with the descriptive value displayed in the control.

  property ListSource: TDataSource; [rw]

  

Datasource with the lookup dataset for the control.

  property LookupCache: Boolean; [rw]

  

Indicates if caching is enabled for fields in the lookup dataset.

  property NullValueKey: TShortCut; [rw]

  

Keyboard shortcut used to assign the empty key value to the control.

  property EmptyValue: string; [rw]

  

Value used as the empty field value in the DataField for the control.

  property DisplayEmpty: string; [rw]

  

Descriptive text displayed for the EmptyValue in the control.

  property OnClick: TNotifyEvent;

  

Notification handler for mouse clicks.

  property OnContextPopup: TContextPopupEvent;

  

Invoked when a context-sensitive pop-up menu is requested.

  property OnDblClick: TNotifyEvent;

  

Event Handler for double mouse clicks.

  property OnDragDrop: TDragDropEvent;

  

This handler determines the action on an drop onto this control, in a drag-drop operation.

  property OnDragOver: TDragOverEvent;

  

Event handler for a control being dragged over this control.

  property OnEditingDone: TNotifyEvent;

  

Event handler signalled when editing is done.

  property OnEndDrag: TEndDragEvent;

  

Notification handler for the end of a dragging operation.

  property OnEnter: TNotifyEvent;

  

Handler for control receiving the focus.

  property OnExit: TNotifyEvent;

  

Handler for control loosing the focus; This is a good place for checking the finished user input.

  property OnKeyPress: TKeyPressEvent;

  

Handler for a character entered by the user.

  property OnKeyDown: TKeyEvent;

  

Handler for keyboard key pressed.

  property OnKeyUp: TKeyEvent;

  

Handler for keyboard key released.

  property OnMouseDown: TMouseEvent;

  

Event handler for mouse button going down.

  property OnMouseEnter: TNotifyEvent;

  

Event handler for mouse entering the area of the control.

  property OnMouseLeave: TNotifyEvent;

  

Event handler for mouse leaving the area of the control.

  property OnMouseMove: TMouseMoveEvent;

  

Event handler for mouse movement within the control.

  property OnMouseUp: TMouseEvent;

  

Event handler for mouse button going up.

  property OnMouseWheel: TMouseWheelEvent;

  

Event handler for mouse wheel turned.

  property OnMouseWheelDown: TMouseWheelUpDownEvent;

  

Event handler for downward movement of mouse wheel.

  property OnMouseWheelUp: TMouseWheelUpDownEvent;

  

Event handler for upward movement of the mouse wheel.

  property OnResize: TNotifyEvent;

  

Notification handler for a resize of the control.

  property OnStartDrag: TStartDragEvent;

  

Event handler for the start of a dragging operation.

  property OnUTF8KeyPress: TUTF8KeyPressEvent;

  

Handler for a character entered by the user.

  property Options: TListBoxOptions;

  

Contains options enabled for the list box control.

  property ParentBiDiMode: Boolean;

  

Allows to use the BiDiMode settings in the Parent control. Default is true.

  property ParentDoubleBuffered: Boolean;

  

Value from the DoubleBuffered property in a Parent 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 ReadOnly: Boolean;

  

Indicates if the linked dataset for the control cannot be modified.

  property ScrollListDataset: Boolean; [rw]

  

Indicates if the look-up data set is scrolled for a new value in the control.

  property ShowHint: Boolean;

  

Enables the Hint display.

  property Sorted: Boolean;

  

Determines whether the list entries are sorted in alphanumeric order.

  property TabOrder: TTabOrder;

  

Determines the sequence of control navigation when the user presses the Tab key.

  property TabStop: Boolean;

  

Allows the user to navigate to this control, by pressing the Tab key.

  property TopIndex: Integer;

  

Index of the first visible (or top-most) item.

  property Visible: Boolean;

  

Allows the control, and all of its children, to be displayed or hidden.

end;

Inheritance

TDBLookupListBox

  

Implements a data-aware listbox control with database lookup capabilities.

|

TCustomDBListBox

  

Specifies a data-aware listbox control.

|

TCustomListBox

  

The base class for TListBox.

|

TWinControl

  

The base class for controls 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

TDBLookupListBox is a TCustomDBListBox descendant which implements a data-aware listbox with database lookup capabilities.

TDBLookupListBox allows selection of a value from a list of items, and stores the value to a field in a linked dataset. The database lookup feature allows a separate dataset to be used which contains the values for the items available in the control. Individual fields can be specified for both the stored value and the the associated display value. Internally, it uses a TDBLookup component to enable the database lookup feature.

In addition, the control can be used in an unbound mode where either the DataSource or the DataField is not defined for the control. This allows the lookup dataset to synchronized when the current selection in the control is changed, but prevents the selected value from being stored in the linked dataset.

Use ListSource to provide access to the lookup dataset used in the control. Use ListField or ListFieldIndex to specify the field name or ordinal position in the lookup dataset displayed in the listbox. Use KeyField to specify the field name in the lookup dataset with the value stored in the DataField for the control. Use KeyValue to read or write the value for the KeyField in the lookup dataset.

See also

TDBLookupListBox.IsUnbound

  

Indicates if the control is being used in the "unbound" mode.

TDBLookupListBox.DataSource

  

Provides access to the linked dataset for the control.

TDBLookupListBox.DataField

  

Name for the field in the linked dataset used in the control.

TDBLookupListBox.ListSource

  

Datasource with the lookup dataset for the control.

TDBLookupListBox.ListField

  

Field name with the descriptive value displayed in the listbox.

TDBLookupListBox.ListFieldIndex

  

Ordinal position of the field in the lookup dataset with the descriptive value displayed in the control.

TDBLookupListBox.KeyField

  

Field name in the lookup dataset with the value for the control.

TDBLookupListBox.KeyValue

  

Accesses the value for the KeyField in the lookup dataset.

TDBLookup

  

TDBLookup - used as source of data by TDBLookupListBox or TDBLookupComboBox, to find data from a lookup table.

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