Unit: WebCtrls

TCaptureStartEvent = function (Sender: TObject; Button: Integer;
      ShiftKey, CtrlKey, AltKey: Boolean; X,Y: Integer): Boolean of
      object

Available In: Client Applications

The TCaptureStartEvent type is a common event type used by the OnCaptureStart properties of a control when the mouse pointer is pressed or touch input occurs, and gives the control an opportunity to capture the mouse pointer or touch input.

The Sender parameter represents the class instance that triggered the event. The Button parameter represents the ordinal button code of the mouse button pressed, and the ShiftKey, CtrlKey, AltKey parameters represent whether the Shift, Control, and/or Alt keys were also pressed. The X and Y parameters indicate the horizontal and vertical position of the mouse pointer or touch input, in pixels, relative to the bounds of the control that triggered the event.

The ordinal mouse button values are defined in the WebUI unit, and are as follows:

MB_NONE = 0;
MB_LEFT = 1;
MB_MIDDLE = 2;
MB_RIGHT = 3;