TDBMemo class

In unit DBCtrls

TDBMemo is a data-aware Memo box to process the multi-line text of a single field in a dataset.

Declaration

pascal

TDBMemo = class(TCustomMemo)

Inheritance

Description

TDBMemo is a TCustomMemo descendant which implements a data-aware memo control. Like its ancestor, TDBMemo can be used to display or edit multi-line textual content. It extends the ancestor class to provide properties which define the datasource and field name with the value maintained in the control. For situations where data-awareness is not needed, use the TMemo control.

Internally, the control uses a TFieldDataLink to maintain an association between the control and its datasource, dataset, and field.

Use DataSource to assign the component with the linked dataset for the control.

Use DataField to specify the name of the field in the linked dataset with the value for the control.

Use the AutoDisplay property to control whether the field content is automatically displayed during record navigation in the linked dataset. When AutoDisplay is set to False, the DisplayLabel for the Field is shown in the control and it content must be loaded by calling the LoadMemo method.

Properties

`Field`	public	Provides access to the field definition for the data-aware control.
`Align`	published	Specifies the placement of the control on its Parent control.
`Alignment`	published	The horizontal alignment for the text in the control (left, right, or centered).
`Anchors`	published	The set of anchor definitions for this control.
`AutoDisplay`	published	AutoDisplay - if True, automatically displays the data when loaded from the linked dataset.
`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	Controls the character case applied to values entered in 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, as a string (i.e. cannot be referred to as an Index).
`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.
`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.
`MaxLength`	published	The maximum length of the value entered in Text, or 0 (zero) for unlimited length.
`ParentBiDiMode`	published	Indicates whether the BiDiMode settings in the Parent control are used.
`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 that the text in the control cannot be modified.
`ScrollBars`	published	Defines the vertical and/or horizontal scrollbars used in the 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.
`WantReturns`	published	Allows the user to insert Return characters (line breaks) into the text.
`WantTabs`	published	Allows Tab characters to be entered into the text.
`WordWrap`	published	Allows long lines (paragraphs) to wrap into multiple display lines.

Methods

`GetReadOnly`	protected	Gets the value for the ReadOnly property.
`SetReadOnly`	protected	Sets the value for the ReadOnly property.
`DataChange`	protected	DataChange - if Data changed, loads the new data into the appropriate part of the Field.
`Notification`	protected	Handles the notification when a component is added or removed from the control.
`UpdateData`	protected	UpdateData - if data changed, copy new text via the datalink.
`Change`	protected	Performs actions needed when the value for the control has been changed.
`KeyDown`	protected	Handles key down events in the data-aware control.
`KeyPress`	protected	Signals the OnKeyPress event handler (when assigned).
`WndProc`	protected	The general message handler for this control.
`WSRegisterClass`	protected	Registers the widgetset class created for new instances of the control.
`Create`	public	Constructor for the class instance.
`Destroy`	public	Destroy - destructor for TDBMemo: frees datalinks then calls inherited Destroy.
`EditingDone`	public	Called when editing has been completed in the control.
`LoadMemo`	public	Loads the lines of text for the memo from the field in the linked data set.
`ExecuteAction`	public	Provides support for TBasicAction in the control.
`UpdateAction`	public	Updates the specified action to reflect the current state in the linked dataset.

Events

`OnChange`	published	Event handler signalled when the text for the control is changed.
`OnClick`	published	Notification handler for mouse clicks.
`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.
`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 for key down keyboard events.
`OnKeyPress`	published	Event handler signalled for character data entered by the user.
`OnKeyUp`	published	Event handler signalled when a key up event has occurred 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.
`OnResize`	published	Notification handler for a resize of the control.
`OnStartDrag`	published	Event handler signalled for the start of a dragging operation.
`OnUTF8KeyPress`	published	Handler for a character entered by the user.