When you pass a nullable generic from a property, you will need to pass the propertie's .Value member. Like this:new PatientSelectedEventArgs(boPatientSearch1.MRN, boPatientSearch1.LASTNAME, boPatientSearch1.FIRSTNAME, boPatientSearch1.BIRTHDATE.Value, boPatientSearch1.GENDER, boPatientSearch1.SSN);
Otherwise, you're passing a NullableGeneric value into an actual value.