ByVal References in Microsoft Forms
The ByVal keyword in Microsoft Forms indicates that an argument is passed as a value; this is the standard meaning of ByVal in Visual Basic. However, in Microsoft Forms, you can use ByVal with a ReturnBoolean, ReturnEffect, ReturnInteger, or ReturnString object. When you do, the value passed is not a simple data type; it is a pointer to the object.
When used with these objects, ByVal refers to the object, not the method of passing parameters. Each of the objects listed above has a Value property that you can set. You can also pass that value into and out of a function. Because you can change the values of the object's members, events produce results consistent with ByRef behavior, even though the event syntax says the parameter is ByVal.
Assigning a value to an argument associated with a ReturnBoolean, ReturnEffect, ReturnInteger, or ReturnString is no different from setting the value of any other argument. For example, if the event syntax indicates a Cancel argument used with the ReturnBoolean object, the statement is still valid, just as it is with other data types.