TDBComboBox class
TDBComboBox is a data-aware version of
TComboBox which
allows selection of a value from a list of entries into a database field.Declaration
TDBComboBox = class(TCustomDBComboBox)Inheritance
- TDBComboBox
- TCustomDBComboBox
- TCustomComboBox
- TWinControl
- TControl
- TLCLComponent
- TComponent
- TPersistent
- TObject
Description
TDBComboBox has properties similar to
TComboBox and
TCustomComboBox. It consists of an Edit Box which is the
Data-aware part of the component, and a drop-down list box.
In a typical application a user would be presented with the drop-down list, would make a selection and then this would appear in the edit box and become the data value for that cell in the database.
As an example, a list of countries might be presented, and the selected value from the list would be used to populate the appropriate field ('Country') in that record of the database.
See also
Properties
Align | published | Specifies the placement of the control on its Parent control. |
Anchors | published | The set of anchor definitions for this control. |
ArrowKeysTraverseList | published | Indicates if keyboard Arrow (or cursor) keys can be used to move through the list. |
AutoComplete | published | Positions the list box using partial text matching. |
AutoCompleteText | published | Options for the behavior of the Auto-Complete feature. |
AutoDropDown | published | Indicates if the drop-down is automatically displayed when the control gets the input focus. |
AutoSelect | published | Selects the entire content of the edit box when the control receives the focus. |
AutoSize | published | Allows automatic adjustment of the size for the control, according to its content. |
BiDiMode | published | Indicates whether text controls use in bi-directional reading. |
BorderSpacing | published | Determines the inner and outer border spacing for this control. |
BorderStyle | published | Indicates the border style displayed around the control. |
CharCase | published | Indicates the case conversion applied to the value entered in the edit box for the control. |
Color | published | The background color for the control. |
Constraints | published | Contains the minimum and maximum Width and Height for the control. |
DataField | published | The name of the Field which provides the values displayed in the control. |
DataSource | published | Provides access to the dataset with content for the control. |
DoubleBuffered | published | When enabled, it reduces flicker when the control is painted. |
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. |
DropDownCount | published | The maximum number of Items visible in the drop-down list for the control. |
Enabled | published | Determines whether the control responds to mouse or keyboard input. |
Font | published | The font to be used for text display in this control. |
ItemHeight | published | The default height of an item in the drop-down for the control. |
Items | published | The list of items displayed in the combo-box control. |
ItemWidth | published | The minimum width of the items in the drop-down list. |
MaxLength | published | The maximum length for text entered in the edit box for the 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. |
ParentDoubleBuffered | published | Value for the DoubleBuffered property in a Parent control. |
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. |
ReadOnly | published | Indicates if the control is prevented from changing the field value in its linked dataset. |
ShowHint | published | Enables Hint display for the control. |
Sorted | published | Determines whether the list entries are sorted in alphanumeric order. |
Style | published | Controls the appearance and behavior for the combo-box. |
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 | Indicates if the control is visible on its parent. |
Methods
DataChange | protected | DataChange - updates the text if it has changed. |
KeyPress | protected | Applies standard keystrokes to the control. |
UpdateData | protected | Applies the changed value for the control to the field in its linked dataset. |
Events
OnChange | published | Event handler signalled for user changes to the text in the edit box. |
OnChangeBounds | published | Event handler signalled when the Bounds for the control have been changed. |
OnClick | published | Notification handler for mouse clicks. |
OnCloseUp | published | Handler invoked when the drop-down list closes. |
OnContextPopup | published | Invoked when a context-sensitive pop-up menu is requested. |
OnDblClick | published | Event handler signalled when a mouse double click occurs in the control. |
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. |
OnDrawItem | published | Handler for special painting of an item (in owner-draw mode). |
OnDropDown | published | Handler invoked when the list has dropped down. |
OnEditingDone | published | Event handler signalled when editing is completed for the control. |
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. |
OnKeyDown | published | Event handler signalled when a key is down while the control has focus. |
OnKeyPress | published | Event handler signalled when a key is pressed while the control has focus. |
OnKeyUp | published | Event handler signalled when when a key is released while the control has focus. |
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. |
OnSelect | published | Handler invoked when an item is selected. |
OnStartDrag | published | Event handler signalled for the start of a dragging operation. |
OnUTF8KeyPress | published | Handler for a character entered by the user. |
Inherited
From TCustomDBComboBox (22)
Change CloseUp Create Destroy DetectedEvents DoEdit DoMouseWheel DoOnChange DoOnCloseUp DoOnSelect EditingDone ExecuteAction Field ItemIndex KeyDown LMDeferredEdit Notification Select Text UpdateAction UpdateRecord WndProc
From TCustomComboBox (60)
AddHistoryItem AddItem AdjustDropDown AutoSelected CanShowEmulatedTextHint Canvas Clear ClearSelection CMWantSpecialKey CreateParams DestroyWnd DoAutoAdjustLayout DoAutoCompleteSelect DoEnter DoExit DrawItem DropDown DroppedDown EmulatedTextHintStatus GetControlClassDefaultSize GetItemCount GetItemHeight GetItemIndex GetItems GetMaxLength GetSelLength GetSelStart GetSelText InitializeWnd IntfGetItems KeyUp KeyUpAfterInterface LMChanged MatchListItem MeasureItem MouseUp OnGetItems OnMeasureItem RealGetText RealSetText SelectAll SelectItem SelLength SelStart SelText SetDropDownCount SetDroppedDown SetItemHeight SetItemIndex SetItems SetMaxLength SetSelLength SetSelStart SetSelText SetSorted SetStyle ShouldAutoAdjust TextHint UTF8KeyPress WSRegisterClass
From TWinControl (219)
AddControl AdjustClientRect AlignControls AllAutoSized AutoAdjustLayout AutoSizeDelayed AutoSizeDelayedHandle AutoSizeDelayedReport AutoSizePhases BeginUpdateBounds BorderWidth BoundsLockCount BroadCast Brush BrushCreated CachedClientHeight CachedClientWidth CalculatePreferredSize CanFocus CanSetFocus CanTab ChangeScale ChildClassAllowed ChildHandlesCreated ChildKey ChildSizing ClientRectNeedsInterfaceUpdate CMBiDiModeChanged CMBorderChanged CMDoubleBufferedChanged CMEnabledChanged CMEnter CMExit CMParentDoubleBufferedChanged CMShowHintChanged CMShowingChanged CMVisibleChanged CNChar CNKeyDown CNKeyUp CNSysKeyDown CNSysKeyUp ContainsControl ControlAtPos ControlCount ControlKeyDown ControlKeyUp Controls ControlsAligned CreateBrush CreateDockManager CreateHandle CreateParented CreateParentedControl CreateSubClass CreateWnd CustomAlignInsertBefore CustomAlignPosition DefaultHandler DefWndProc DesignerDeleting DestroyHandle DialogChar DisableAlign DoAddDockClient DoAdjustClientRectChange DoAlignChildControls DoAllAutoSize DoAutoSize DoChildSizingChange DockClientCount DockClients DockDrop DockManager DockOver DockSite DoConstraintsChange DoDockClientMsg DoDockOver DoDragMsg DoFlipChildren DoFloatMsg DoGetDockCaption DoKeyDownBeforeInterface DoKeyPress DoKeyUpBeforeInterface DoRemainingKeyDown DoRemainingKeyUp DoRemoveDockClient DoSendBoundsToInterface DoSendShowHideToInterface DoSetBounds DoUnDock DoUndockClientMsg DoUTF8KeyPress EnableAlign EndUpdateBounds EraseBackground FinalizeWnd FindChildControl FindNextControl FixDesignFontsPPIWithChildren FixupTabList FlipChildren Focused FontChanged FormEndUpdated GetAdjustedLogicalClientRect GetBorderStyle GetChildren GetChildrenRect GetClientOrigin GetClientRect GetControlIndex GetControlOrigin GetDeviceContext GetDockCaption GetEnumeratorControls GetEnumeratorControlsReverse GetMouseCapture GetParentHandle GetPreferredSizeClientFrame GetSiteInfo GetTabOrderList GetTextLen GetTopParentHandle Handle HandleAllocated HandleNeeded InsertControl IntfGetDropFilesTarget IntfUTF8KeyPress Invalidate InvalidateBoundsRealized InvalidateClientRectCache InvalidatePreferredChildSizes IsClientHeightStored IsClientWidthStored IsControlMouseMsg IsFlipped IsResizing IsSpecialSubControl KeyDownAfterInterface KeyDownBeforeInterface KeyUpBeforeInterface Loaded LockRealizeBounds MainWndProc NotifyControls OnAlignInsertBefore OnAlignPosition OnDockDrop OnDockOver OnGetDockCaption OnGetSiteInfo OnUnDock PaintControls PaintHandler PaintTo PaintWindow ParentFormHandleInitialized ParentHandlesAllocated ParentWindow PerformTab ReAlign RealizeBounds RealizeBoundsRecursive ReloadDockedControl RemoveControl RemoveFocus Repaint ScaleBy ScaleControls ScrollBy ScrollBy_WS SelectFirst SelectNext SendDialogChar SendMoveSizeMessages SetBorderStyle SetBounds SetChildZPosition SetColor SetControlIndex SetDockManager SetFocus SetShape SetTempCursor ShowControl Showing UnlockRealizeBounds Update UpdateControlState UpdateDockCaption UpdateShowing UseDockManager VisibleDockClientCount WindowHandle WMChar WMContextMenu WMDestroy WMEnter WMEraseBkgnd WMExit WMKeyDown WMKeyUp WMKillFocus WMMove WMNotify WMPaint WMSetFocus WMShowWindow WMSize WMSysChar WMSysKeyDown WMSysKeyUp WMWindowPosChanged WriteLayoutDebugReport WSSetText
From TControl (323)
AccessibleDescription AccessibleName AccessibleRole AccessibleValue Action ActionChange ActionLink ActiveDefaultControlChanged AddHandler AddHandlerOnBeforeDestruction AddHandlerOnChangeBounds AddHandlerOnEnabledChanged AddHandlerOnEnabledChanging AddHandlerOnKeyDown AddHandlerOnMouseWheel AddHandlerOnResize AddHandlerOnVisibleChanged AddHandlerOnVisibleChanging AdjustSize AnchorAsAlign AnchorClient AnchoredControlCount AnchoredControls AnchorHorizontalCenterTo AnchorParallel AnchorSame AnchorSide AnchorSideBottom AnchorSideChanged AnchorSideLeft AnchorSideRight AnchorSideTop AnchorToCompanion AnchorToNeighbour AnchorVerticalCenterTo AssignTo AutoSizing AutoSizingAll AutoSizingLockCount BaseBounds BaseParentClientSize BeforeDestruction BeforeDragStart BeginAutoDrag BeginAutoSizing BeginDrag BoundsChanged BoundsRect BoundsRectForNewParent BringToFront CalculateDockSizes CanAutoSize Caption CaptureChanged CaptureMouseButtons ChangeBounds Changed CheckChildClassAllowed CheckNewParent CheckOnChangeBounds Click ClientHeight ClientOrigin ClientRect ClientToParent ClientToScreen ClientWidth CMChanged CMCursorChanged CMHintShow CMHitTest CMMouseEnter CMMouseLeave CMParentBiDiModeChanged CMParentColorChanged CMParentFontChanged CMParentShowHintChanged CMSysFontChanged CMTextChanged CNPreferredSizeChanged ColorIsStored ConstrainedResize ControlFontClass ControlOrigin ControlState ControlStyle ControlToScreen CreateAccessibleObject CreateControlBorderSpacing CreateFloatingDockSite Cursor DblClick DefineProperties DesktopFont DisableAutoSizing DoBorderSpacingChange DoCallKeyEventHandler DoCallMouseWheelEventHandler DoCallNotifyHandler Dock Docked DockOrientation DockTrackNoTarget DoContextPopup DoDock DoEndDock DoEndDrag DoFixDesignFontPPI DoMouseDown DoMouseUp DoMouseWheelDown DoMouseWheelHorz DoMouseWheelLeft DoMouseWheelRight DoMouseWheelUp DoOnChangeBounds DoOnParentHandleDestruction DoOnResize DoOnShowHint DoScaleFontPPI DoStartDock DoStartDrag DragCanceled DragDrop Dragging DragOver EnableAutoSizing EnabledChanged EnabledChanging EndAutoSizing EndDrag ExecuteCancelAction ExecuteDefaultAction FindSubComponent FixDesignFontsPPI Floating FloatingDockSiteClass ForeignAnchorSideChanged FormIsUpdating GetAccessibleObject GetAction GetActionLinkClass GetAnchorsDependingOnParent GetCachedText GetCanvasScaleFactor GetChildAccessibleObjectAtPos GetClientScrollOffset GetColorResolvingParent GetCursor GetDefaultColor GetDefaultDockCaption GetDefaultHeight GetDefaultWidth GetDockEdge GetDragImages GetEnabled GetFloating GetFloatingDockSiteClass GetLogicalClientRect GetMousePosFromMessage GetPalette GetParentBackground GetParentComponent GetPopupMenu GetPreferredSize GetRGBColorResolvingParent GetScrolledClientRect GetSelectedChildAccessibleObject GetSidePosition GetTextBuf GetTopParent HandleObjectShouldBeVisible HasHelp HasParent Height HeightIsAnchored HelpContext HelpKeyword HelpType Hide Hint HostDockSite InitiateAction InvalidateControl InvalidatePreferredSize IsAParentAligning IsBorderSpacingInnerBorderStored IsCaptionStored IsControl IsControlVisible IsEnabled IsParentColor IsParentFont IsParentOf IsProcessingPaintMsg IsRightToLeft IsVisible Left LMCaptureChanged LoadedAll LRDockWidth ManualDock ManualFloat MouseCapture MouseDown MouseEnter MouseInClient MouseLeave MouseMove OnConstrainedResize OnEndDock OnMouseWheelHorz OnMouseWheelLeft OnMouseWheelRight OnQuadClick OnResize OnShowHint OnStartDock OnTripleClick Parent ParentBackground ParentDestroyingHandle ParentFontChanged ParentToClient Perform PositionDockRect QuadClick ReadBounds ReadState Refresh RemoveAllHandlersOfObject RemoveHandler RemoveHandlerOnBeforeDestruction RemoveHandlerOnChangeBounds RemoveHandlerOnEnabledChanged RemoveHandlerOnEnabledChanging RemoveHandlerOnKeyDown RemoveHandlerOnMouseWheel RemoveHandlerOnResize RemoveHandlerOnVisibleChanged RemoveHandlerOnVisibleChanging ReplaceDockedControl RequestAlign Resize Scale96ToFont Scale96ToForm Scale96ToScreen ScaleConstraints ScaleDesignToForm ScaleFontsPPI ScaleFontTo96 ScaleFontToScreen ScaleFormTo96 ScaleFormToDesign ScaleScreenTo96 ScaleScreenToFont ScreenToClient ScreenToControl SendToBack SessionProperties SetAction SetAlign SetAnchors SetAutoSize SetBiDiMode SetBoundsKeepBase SetCursor SetDragMode SetEnabled SetHint SetInitialBounds SetName SetParent SetParentBackground SetParentBiDiMode SetParentComponent SetTextBuf SetVisible SetZOrder Show ShowHelp TBDockHeight TextChanged Top TripleClick UndockHeight UndockWidth UpdateAnchorRules UpdateBaseBounds UpdateMouseCursor UpdateRolesForForm UseRightToLeftAlignment UseRightToLeftReading UseRightToLeftScrollBar VisibleChanged VisibleChanging Width WidthIsAnchored WindowProc WMCancelMode WMLButtonDBLCLK WMLButtonDown WMLButtonQuadCLK WMLButtonTripleCLK WMLButtonUp WMMButtonDBLCLK WMMButtonDown WMMButtonQuadCLK WMMButtonTripleCLK WMMButtonUp WMMouseHWheel WMMouseMove WMMouseWheel WMRButtonDBLCLK WMRButtonDown WMRButtonQuadCLK WMRButtonTripleCLK WMRButtonUp WMXButtonDBLCLK WMXButtonDown WMXButtonQuadCLK WMXButtonTripleCLK WMXButtonUp
From TLCLComponent (6)
DecLCLRefCount GetWSComponentClass IncLCLRefCount LCLRefCount NewInstance WidgetSetClass
From TComponent (62)
_AddRef _Release CanObserve ChangeName ComObject ComponentCount ComponentIndex Components ComponentState ComponentStyle DesignInfo DestroyComponents Destroying FindComponent FreeNotification FreeOnRelease GetChildOwner GetChildParent GetDeltaStreams GetEnumerator GetIDsOfNames GetNamePath GetObservers GetOwner GetTypeInfo GetTypeInfoCount iicrGetComponent InsertComponent Invoke IsImplementorOf Loading Name ObserverAdded Observers OnGetDeltaStreams Owner PaletteCreated QueryInterface ReadDeltaState ReadDeltaStream ReferenceInterface RemoveComponent RemoveFreeNotification RemoveFreeNotifications SafeCallException SetAncestor SetChildOrder SetDesigning SetDesignInstance SetInline SetSubComponent Tag ToString TToStringNameMode Updated UpdateRegistry Updating ValidateContainer ValidateInsert ValidateRename VCLComObject WriteState
From TPersistent (4)
Assign FPOAttachObserver FPODetachObserver FPONotifyObservers
From TObject (35)
AfterConstruction CheckDisposed ClassInfo ClassName ClassNameIs ClassParent ClassType CleanupInstance DefaultHandlerStr Dispatch DispatchStr Disposed DisposeOf Equals FieldAddress Free FreeInstance GetDisposed GetHashCode GetInterface GetInterfaceByStr GetInterfaceEntry GetInterfaceEntryByStr GetInterfaceTable GetInterfaceWeak GetLastCastErrorInfo InheritsFrom InitInstance InstanceSize MethodAddress MethodName QualifiedClassName StringMessageTable SystemHasExtendedRTTI UnitName
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