Persistence ignorance and custom models

So far, we have used generated classes as our models. We will now look at creating a custom model and will add persistence ignorance to our design.

Trade-offs of generated models

The Microsoft technology stack provides plenty of solutions that allow for getting up and running with models that support change notifications via INotifyPropertyChanged. As with everything in software development, there are trade-offs to be considered when determining what type of architecture you need; the advantages and disadvantages of using generated models are shown as follows:

Advantages	Disadvantages
Quick to develop	Couples Presentation with data access
Models are generated for you	Changing data access requires difficult refactoring of presentation code.
Generated code for change notification	Encourages database centric model

You should be familiar with the advantages listed previously at this point, so let's talk a bit about the disadvantages. When we needed to change...