Metalama//Commented Examples/Change Tracking
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Example: Change Tracking

The Dirty Flag pattern is a design pattern that tracks changes to an object's state by maintaining a boolean flag indicating whether the object's properties or fields have been modified. This pattern is commonly used in user interface programming, where it is necessary to determine quickly whether an object's state has changed so that the Save button can be dynamically enabled. In .NET, objects that support this feature must implement the IChangeTracking interface.

Implementing the Dirty Flag pattern typically requires adding a large amount of boilerplate code to each class that needs to track changes to its state. However, aspect-oriented programming (AOP) techniques can automate this repetitive and error-prone task. In this example, we will see how to create an aspect that automates this pattern, reducing the boilerplate code you must write and maintain while improving code quality and consistency.

Article Description
1. Getting started Provides a minimal implementation of the change tracking pattern.
2. Verifying code Reports errors if the manual implementation of the pattern does not respect the conventions of the pattern.
3. Integrating with INotifyPropertyChanged Raises PropertyChange notifications when the IsChanged property has changed.
4. Reverting changes Adds support for the RevertChanges method.
Limitations This article discusses the limitations of the above aspects.