BindingMode
The direction of changes propagation for bindings.
Default = 0
When used in Bindings, indicates that the Binding should use the DefaultBindingMode. When used in BindableProperty declaration, defaults to BindingMode.OneWay.
OneWay = 2
Indicates that the binding should only propagates changes from source (usually the View Model) to target (the BindableObject). This is the default mode for most BindableProperty values.
OneWayToSource = 3
Indicates that the binding should only propagates changes from target (the BindableObject) to source (usually the View Model). This is mainly used for read-only BindableProperty values.
TwoWay = 1
Indicates that the binding should propagates changes from source (usually the View Model) to target (the BindableObject) in both directions.