How to Generate Events Automatically at Predefined Intervals

ID: Q78599

The information in this article applies to:

Microsoft Visual Basic Standard and Professional Editions for Windows, versions 2.0, 3.0
Microsoft Visual Basic programming system for Windows, version 1.0

Timer controls can be used to automatically generate an event at predefined intervals. This interval is specified in milliseconds, and can range from 0 to 65535 inclusive.

Timer event processing will not be interrupted by new timer events. This is because of the way that Windows notifies an application that a timer event has occurred. Instead of interrupting the application, Windows places a WM_TIMER message in its message queue. If there is already a WM_TIMER message in the queue from the same timer, the new message will be consolidated with the old one.

After the application has completed processing the current timer event, it checks its message queue for any new messages. This queue may have new WM_TIMER messages to process. There is no way to tell if any WM_TIMER messages have been consolidated.

Additional query words: 2.00 3.00


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Last Reviewed: June 25, 1999