Business Validation Logic Code Smell

Question

Consider the following code:

partial class OurBusinessObject {
    partial void OnOurPropertyChanged() {
        if(ValidateOurProperty(this.OurProperty) ==          


        

Answer 1

I'd say, implement PropertyChanging and allow the business logic to approve/deny a value, and then afterwards, throw an exception for invalid values.

This way, you don't ever have an invalid value. That, and you should never change a user's information. What if a user adds an entry to the database, and keeps track of it for his own records? Your code would re-assign the value to the default, and he's now tracking the wrong information. Its better to inform the user ASAP.