ExpressionEdit

Inheritance Hierarchy

Description

The ExpressionEdit component is used to edit an expression.

Working with the Component

To provide component work, link the Expression property to any object expression (for example, calculated table field formula). Further work on creating an expression is similar to the work with the TermEdit component expression. All current changes are available in the Text property (text displayed in the component) and the Formula property (the expression, which the calculation is based on). To update the expression specified in the Expression property, the UpdateExpression method is used.

NOTE. The ExpressionEdit component and the ExpressionEditEx component differ in their internal implementation.

Properties of the ExpressionEdit Component

	Property name	Brief description
	Align	The Align property determines behavior of the component when its parent component is resized.
	AllowDrag	The AllowDrag property determines whether an object can be dragged from the component.
	AllowDrop	The AllowDrop property determines whether the component can accept a dragged object.
	Anchors	The Anchors property returns settings that determine the percentage of the size change for the current component when the parent component is resized.
	AutoSelect	The AutoSelect property determines whether component text is selected when the component gets focused.
	BorderStyle	The BorderStyle property determines a component border style.
	Brush	The Brush property determines the brush that is used to fill component area.
	CanUndo	The CanUndo property returns True if it is possible to undo text changes in the component.
	CharacterCasing	The CharacterCasing property determines the case of the entered characters.
	ClientHeight	The ClientHeight property is used to receive or specify the height of the component’s client area.
	ClientWidth	The ClientWidth property is used to receive or specify the width of the component’s client area.
	Color	The Color property determines a component background color.
	ComponentCount	The ComponentCount property returns the number of child components.
	Components	The Components property returns the child component.
	Cursor	The Cursor property determines the look of the cursor over the component.
	Data	The Data property is used to store any custom data.
	Enabled	The Enabled property determines whether the component is available for the user.
	EnableHyperlinks	The EnableHyperlinks property determines whether it is possible to display a term as a hyperlink.
	Expression	The Expression property determines the expression located in the component.
	Focused	The Focused property returns True if the focus is set on the component.
	Font	The Font property determines the set of characteristics describing the font that is used to display text.
	Formula	The Formula property determines a term formula.
	Height	The Height property determines component height.
	HelpContext	The HelpContext property determines a unique index for the context help section for this component.
	HideSelection	The HideSelection property determines whether the selected component text remains the same when the focus moves to another component.
	Hint	The Hint property determines a component tooltip text.
	Hyperlink	The Hyperlink property determines whether the expression, which index is an input parameter, is a hyperlink.
	Left	The Left property determines the coordinate of the left border of the component.
	MaxLength	The MaxLength property determines the maximum length of the entered text.
	Modified	The Modified property returns True if the component text has been changed.
	Name	The Name property determines a component name.
	Parent	The Parent property determines a parent component.
	ParentColor	The ParentColor property determines whether the component inherits the color of the parent component.
	ParentFont	The ParentFont property determines whether the component uses the font of the parent component.
	ParentShowHint	The ParentShowHint property determines whether a tooltip is displayed.
	PopupMenu	The PopupMenu property determines the context menu opened by clicking the component with the additional mouse button.
	ReadOnly	The ReadOnly property determines whether the user can change component text.
	Scrolls	The Scrolls property returns parameters of component's scrollbars.
	SelLength	The SelLength property determines the number of characters selected in the component text.
	SelStart	The SelStart property determines the cursor position, from which to start text selection in the component.
	SelText	The SelText property determines the text selected in the component.
	ShowHint	The ShowHint property enables and disables showing a component tooltip.
	TabOrder	The TabOrder property determines the component position in the tab order.
	TabStop	The TabStop property determines whether the component is focused when the TAB key is pressed.
	Tag	The Tag property is not used by the compiler. The user can change the value of the Tag property and use it as he wishes.
	Terms	The Terms property returns the terms collection.
	Text	The Text property determines the row identifying a component for the user.
	Top	The Top property determines the coordinate of the top border of the component.
	Visible	The Visible property determines visibility of the component during execution.
	WantReturns	The WantReturns property determines whether a carriage return symbol can be inserted into the edited text.
	WantTabs	The WantTabs property determines whether a tab symbol can be inserted into the edited text.
	Width	The Width property determines component width.
	WordWrap	The WordWarp property determines, whether the lines exceeding component length are wrapped to a new line.

Methods of the ExpressionEdit Component

	Method name	Brief description
	BeginUpdate	The BeginUpdate method disables a set of internal mechanisms for accelerating insertion of terms into the component.
	Clear	The Clear method deletes all text in the component.
	ClearSelection	The ClearSelection method deletes all text selected in the component.
	ClearUndo	The ClearUndo method is used to fix the changes of the Text property.
	ClientToScreen	The ClientToScreen method converts the coordinates of a point specified relative to the component coordinate system into screen coordinates.
	CopyToClipboard	The CopyToClipboard method enables the user to copy selected data to the clipboard.
	CutToClipboard	The CutToClipboard method enables the user to cut selected data and place it to the clipboard.
	DoDragDrop	The DoDragDrop method enables to start dragging operation.
	EndUpdate	The EndUpdate method restores work of internal mechanisms of the component, which were disabled for acceleration of insertion of terms into the component.
	GetImage	The GetImage method returns the image of the component with all the child components.
	PasteFromClipboard	The PasteFromClipboard method pastes data from the clipboard.
	PutCustom	The PutCustom method enables the user to place the custom term into the specified position.
	PutLiteral	The PutLiteral method enables the user to place the literal term into the specified position.
	PutTerm	The PutTerm method enables the user to place the term into the specified position.
	Reparse	The Reparse method transforms editor text and redistributes terms in the component.
	ScreenToClient	The ScreenToClient method converts screen coordinates of a point into coordinates specified relative to the component coordinate system.
	SelectAll	The SelectAll method selects component text.
	SetFocus	The SetFocus method sets focus to this component.
	Undo	The Undo method undoes the last text change in the component.
	UpdateExpression	The UpdateExpression method updates the expression.

Events of the ExpressionEdit Component

	Event name	Brief description
	OnBeginDrag	The OnBeginDrag event occurs for the component when the user starts to drag an object from the component.
	OnChange	The OnChange event occurs after changing the Text property of the editing component.
	OnClick	The OnClick event occurs if the user clicks the component area.
	OnDblClick	The OnDblClick event occurs if the user double-clicks the component area.
	OnDragDrop	The OnDragDrop event occurs for the component if the user drops a dragged object over it.
	OnDragEnter	The OnDragEnter event occurs when a dragged object crosses the borders of this component.
	OnDragLeave	The OnDragLeave event occurs when a dragged object leaves the borders of this component.
	OnDragOver	The OnDragOver event occurs for the component when the user drags an object over it.
	OnEnter	The OnEnter event occurs when the component receives focus.
	OnExit	The OnExit event occurs when the component loses focus.
	OnHScroll	The OnHScroll event occurs when horizontal scrollbar slider changes its position.
	OnHyperlink	The OnHyperlink event occurs on clicking on the term hyperlink in the expression.
	OnKeyDown	The OnKeyDown event occurs if the component is focused and a keyboard key is pressed.
	OnKeyPress	The OnKeyPress event occurs if the component is focused when the user presses a character key.
	OnKeyPreview	The OnKeyPreview event occurs prior to each event related to key pressing.
	OnKeyUp	The OnKeyUp event occurs if the component is focused and the user releases any button previously pressed.
	OnMouseDown	The OnMouseDown event occurs if the pointer is in component's area and a mouse key is pressed.
	OnMouseEnter	The OnMouseEnter event occurs when mouse cursor enters the component area.
	OnMouseHover	The OnMouseHover event occurs when mouse cursor is held in the component area.
	OnMouseLeave	The OnMouseLeave event occurs when mouse cursor leaves the component area.
	OnMouseMove	The OnMouseMove event occurs on moving the cursor over component.
	OnMouseUp	The OnMouseUp event occurs on releasing mouse button when the cursor is in component area.
	OnMouseWheel	The OnMouseWheel event occurs if the component is focused when the mouse wheel is rotated.
	OnParseTerm	The OnParseTerm event occurs when the editor text is transformed into terms and operands.
	OnVScroll	The OnVScroll event occurs when vertical scrollbar slider changes its position.