Click the “Event” tab in the “Property Sheet” window. You should see five events, all starting with “On...”.
An “event” in the “Property Sheet” window should have been called an “event handler”. An event of a user interface object is usually triggered by an end user. For example, a user can click, double click, press the (left) button of a mouse, release the (left) button of a mouse, or simply move the mouse cursor. These events correspond to the five items listed in the “Event” tab of a label.
But, this is just a label, why is “click” even be an event? If you think this is strange, let’s do this. Switch to “Design View”, and click anywhere that is empty (outside of the form area filled with grid dots). You can confirm that the “Property Sheet” belongs to the form, and yet it, too, has an “On Click” event handler!
Now, let’s click the button so that we focus on a label. Each item listed in the “Event” tab is, as discussed earlier, an event handler. This is how a developer can associated code to execute when the event occurs (on the object). For example, “On Click” specifies the code to execute when the label is clicked.
An event handler is a crucial part of any VBA program that has user interaction, as it ties user triggered events to specific code.