CommandBarComboBox.OnAction Property (Office)
Gets or sets the name of a Visual Basic procedure that will run when the user clicks or changes the value of a CommandBarComboBox control. Read/write.
The use of CommandBars in some Microsoft Office applications has been superseded by the new ribbon component of the Microsoft Office Fluent user interface. For more information, search Help for the keyword "ribbon."
expression A variable that represents a CommandBarComboBox object.
The container application determines whether the value is a valid macro name.