This is definitely a glaring case of RTFM syndrome, but I hadn’t found how to create abstract methods in Visio’s UML Sequence Diagram template. Classes in Visio have an IsAbstract checkbox to indicate if the class is abstract, but there is no “IsAbstract” checkbox for methods. For others who haven’t discovered the less-than-obvious setting and hadn’t bothered to read the help file yet (quoted from the Visio help file):
- In the UML Model Explorer, right-click a package icon, point to New, and then click Class.
- In the UML Class Properties dialog box, type a name for the class, and then click the IsAbstract check box.
- Under Categories, click Operations, click New, and then click the Methods button.
- In the UML Method Properties dialog box, clear the Has method check box, and then click OK.
- In the UML Class Properties dialog box, click the Properties button, set any of the options in the UML Operations Properties dialog box, and then click OK.
Note: The IsPolymorphic check box is selected by default.
- In the UML Class Properties dialog box, click OK.