Abstract
The Observer pattern, quite simply, lets one component notify other components that something has happened. The pattern is used all over the place; for example, when binding data to the UI, we can program domain objects such that, when they change, they generate notifications that the UI can subscribe to and update the visuals.
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Notes
- 1.
By the way, System.EventArgs is an empty type. All it has is a default constructor (empty) and a static member EventArgs.Empty that is a Singleton Null Object (double pattern headshot!) that indicates the event arguments have no data.
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© 2019 Dmitri Nesteruk
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Nesteruk, D. (2019). Observer. In: Design Patterns in .NET. Apress, Berkeley, CA. https://doi.org/10.1007/978-1-4842-4366-4_21
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DOI: https://doi.org/10.1007/978-1-4842-4366-4_21
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Publisher Name: Apress, Berkeley, CA
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