Binding modes and the INotifyPropertyChanged interface

In Chapter 1, What Is the MVVM Design Pattern, we already discussed how data can flow:

• One-way: From ViewModel to View
• One-way-to-source: From View to ViewModel
• One-time: Only once from ViewModel to View
• Two-way: From ViewModel to View and from View to ViewModel

Now, let’s take a look at how this is handled in .NET MAUI.

Binding modes in .NET MAUI

.NET MAUI supports all of these data flows, represented through the Microsoft.Maui.Controls.BindingMode enum: OneWay, OneWayToSource, OneTime and TwoWay. There is in fact a fifth value as well: Default. Remember when we talked about bindable properties earlier in this chapter? When creating a bindable property, there are some optional values we can set. One of those optional parameters is defaultBindingMode. This allows us to set a default binding mode on a bindable property. On Entry, for example, it makes sense to have the default binding mode...