Microsoft has a great record on this here .
But reflection is not used in relation to INotifyPropertyChanged, but when resolving CLR properties.
If the source object is a CLR object and the source property is a CLR property, the Windows Foundation Presentation Engine (WPF) presentation must first use the source to get the TypeDescriptor, and then the request for the PropertyDescriptor. This sequence of operations reflects a potentially very time-consuming job prospect.
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