Designing the Procedure Logic › GUI Event Processing › Windows and Window Controls That Signal Events › CLICK and DOUBLE-CLICK GUI Events

CLICK and DOUBLE-CLICK GUI Events

These events are triggered when the user clicks the left mouse button on a standard list box, list box field (one column of a standard list box), bitmap, or icon.

The click continues to have the display effect it normally does. It causes a row of a list box to be selected or unselected.

The event handler runs after the click has been processed by the control. The event handler may use one of the following statements:

Get Row Clicked
Get Row Highlighted

Some applications use a single CLICK event to invoke processing on a row in a list and others use the DOUBLE-CLICK event.

For Example:

• Given a list of customers, the user clicks once on a row, and the selected customer's details are displayed in the detail area of the same window.
• To invoke a dialog box containing customer details, the user double-clicks on a row in the list.

In these cases, only one event is associated with clicking on a row in the list.

If both a click and double-click are associated with the same list, then both events are performed. This can be counter-intuitive and confusing.

You should come up with a consistent approach throughout the application on what a single click will do and what a double-click will do. The best approach would be to use only one event throughout the application. If this is not possible, then at least avoid using both types of events for the same list if it will produce counter-intuitive results.