| Applies To: | Grid |
Description
If enabled, this event is reported when the user presses a mouse button down whilst over a cell in a Grid. The purpose of this event is to allow an application to display a pop-up Menu or a Locator over a cell in a Grid or to take some other special action.
The default action is to generate a CellMove event which will then position the user on the new cell. This action can be prevented by returning 0 from the callback function, in which case the normally ensuing CellMove event will not occur.
The event message reported as the result of ⎕DQ, or supplied as the right argument to your callback function, is an 9 element vector as follows :
| [1] | Object | ref or character vector |
| [2] | Event | 'CellDown' or 161 |
| [3] | Y | y-position of mouse (number) |
| [4] | X | x-position of mouse (number) |
| [5] | Button | button pressed (number) 1 = left button 2 = right button 4 = middle button |
| [6] | Shift State | sum of shift key codes (number) 1 = Shift key is down 2 = Ctrl key is down 4 = Alt key is down |
| [7] | Cell row | integer |
| [8] | Cell column | integer |
| [9] | Title index | integer |
The y and x position of the mouse are reported relative to the top-left corner of the Grid.
The cell row and column are ⎕IO dependent
If the user clicks over a row title, the value reported for the column is ¯1, and the value reported for Title index is the index of that row title in RowTitles, or, if RowTitles is not defined, the row number. Column titles are handled in a similar fashion.
An application can position the user on a particular cell in a Grid by calling CellDown as a method, but it is recommended that a CellMove event is used instead.