The event is called MouseWheel.

>I am unable to find any scrollwheel events and no events for the the scrollbars. Would you steer me in the correct direction, Please?
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>I have a form that displays a map. The form is much larger than the screen. I would like to be able to use the mouse wheel to move the map up and down the screen. Is there a way to accomplish this?
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>First, set the Scrollbar property of the form to 3 to enable scrollbars. In the ScrollWheel event of each control, you can put the following code:
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>Thisform.SetViewPort( Thisform.ViewPortLeft, Max(0,Thisform.ViewPortTop-Sign(m.nDirection)*16) )
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>This scrolls the form by 16 pixels each time you scroll the wheel. You can use BINDEVENT() to execute this code for every control without adding the code to each one.