If you\u2019re using custom subscriber properties you should be aware of the fact that subscriber properties can be potentially null \u2013 it means that the value of the subscriber property has not been set for a particular subscriber \u2013 it\u2019s different than 0 values or empty strings.<\/p>\n\n\n\n
Performing various operations on null values (such as casting) can result in an error, therefore it is a good idea to check if a particular custom property was set for a subscriber first, using Method signature:<\/p>\n\n\n\nSubscriberHasProperty<\/code> method.<\/p>\n\n\n\n