Timer.Enabled
From Xojo Documentation
Property (As Boolean )
Enables you to turn the Timer on or off.
Notes
When Enabled is True, the Timer is on. Enabled is set to True when you instantiate a Timer. If you turn the Timer off and then turn it on, it resets itself to the start of the period. Defaults to True.
Sample Code
This example is in the Action event of a button control.
Timer1.Enabled = False