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Events


Unit:SDL_rchart
Class:TRChart
Declaration: property OnBeforeRenderData: TRenderEvent;
property OnCanResize: TCanResizeEvent;
property OnClick: TNotifyEvent;
property OnCrossHairMove: TCrossHairMoveEvent
property OnDataRendered: TRenderEvent;
property OnDblClick: TNotifyEvent;
property OnDragDrop;
property OnDragOver;
property OnEndDrag;
property OnKeyDown: TKeyEvent;
property OnKeyPress: TKeyPressEvent;
property OnKeyUp: TKeyEvent;
property OnMouseDown: TMouseEvent;
property OnMouseMove: TMouseMoveEvent;
property OnMouseMoveInChart: TMouseMoveInChartEvent;
property OnMouseUp: TMouseEvent;
property OnMouseWheel;
property OnMouseWheelUp;
property OnMouseWheelDown;
property OnResize: TNotifyEvent;
property OnRubberBand: TSelectRectEvent;
property OnScalesRendered: TRenderEvent;
property OnScaleTickDrawn: TScaleTickDrawnEvent;
property OnSelectRect: TSelectRectEvent;
property OnStartDrag;
property OnTextLabelMove: TTextLabelMoveEvent;
property OnZoomPan: TZoomPanEvent;

The OnCanResize event is triggered when the control is resized. Please note that the OnCanResize event is only available for Delphi 4 and C++Builder 4, or higher versions of these compilers.

The OnClick and the OnDblClick events occur when the user clicks on the component. The events OnMouseMove, OnMouseDown, OnMouseUp, OnMouseWheel, OnMouseWheelUp, and OnMouseWheelDown support the handling of the mouse. The events OnStartDrag, OnDragDrop, OnEndDrag, and OnDragOver control the drap and drop operations. For details on these events see the Delphi documentation.

The OnMouseMoveInChart event returns the mouse position in the chart coordinate system. The OnSelectRect event is triggered when the left mouse button is released during selecting a rectangular area.(1) The OnZoomPan event is triggered when an interactive zoom or pan action is carried out. The OnCrossHairMove event is triggered when any crosshair is moved by the user. The event OnTextLabelMove occurs when the user moves any user-defined text label by mouse interaction.

The OnScaleTickDrawn event is triggered whenever a scale tick has been drawn. The event OnBeforeRenderData occurs immediately before the chart is drawn. The OnScalesRendered  event is triggered after the scales have been drawn internally and before the data will be constructed. The OnDataRendered  event is triggered after the chart has been completed internally and before it is copied to the screen.

Hint: The OnMouseWheel, OnMouseWheelDown, and OnMouseWheelUp events are only received by the component if it has the focus. For example, you could call the method SetFocus in the OnClick event, to ensure that TRChart has the focus after the user clicked it.

Example: Some of these events are used in the following example programs (see http://www.lohninger.com/examples.html for downloading the code): printcht, rchdrag



(1) The OnSelectRect event is a replacement of the deprecated OnRubberBand event.


Last Update: 2014-Sep-14