Radical Documentation
View on GitHub
Primary version
Primary version
  • Home
  • Presentation
    • AbstractViewModel
    • Conventions
      • Bootstrap Conventions
      • Runtime Conventions
      • Conventions override
    • Commands and DelegateCommand
    • IViewResolver
      • Default view behaviors
      • view life cycle events
        • Callback expectations
        • notify messages
    • Message broker MVVM built-in messages
    • Application boot process
      • Application configuration
      • Application shutdown
      • Singleton applications
    • AbstractMementoViewModel
      • Simple ViewModel graphs
      • Collections and complex ViewModel graphs
    • Validation and Validation Services
    • Resources
      • Services as resources
      • ViewModels as resources
  • UI Composition
    • UI Composition
      • Region content lifecycle
      • TabControl region
      • Create a custom region
  • Concepts
    • Inversion of Control
      • Third party DI containers
    • Entities
      • Property System
    • Messaging and Message Broker
      • POCO messages
      • Standalone message handlers
    • Observers
      • PropertyObserver
      • MementoObserver
      • BrokerObserver
  • Memento
    • Change Tracking Service
      • MementoEntity and MementoEntityCollection
      • Handling change tracking:
        • Simple model
        • Collections
        • Complex objects graph
      • Atomic operations
      • Change Tracking Service API
      • Property Metadata for the ChangeTrackingService
      • Handling collection sync
      • Property State
  • Behaviors
    • DataGrid Behaviors
    • Password
    • Generic routed event handler to command behavior
    • Overlay adorner
      • Busy status manager
    • TextBox behaviors:
      • Command
      • Auto select
      • DisableUndoManager (.Net 3.5 only)
  • Markup Extensions
    • Editor binding
    • Auto Command binding
  • How to
    • Get the view of a given view model
    • Bi-directional communication between different windows/views
    • Handle the busy status during async/long running operations
    • Implement a customer improvement program
    • Manage focus
    • Create a splash screen
    • Access view model after view is closed
    • Intercept ViewModels before they are used
  • Upgrade guides
    • Radical Presentation 1.x to Radical 2.x for .NET Core
    • Radical 2.0.0 to Radical 2.1.0
Powered by GitBook
On this page
  1. Memento
  2. Change Tracking Service

Atomic operations

When dealing with a change tracking system based on the memento pattern one of the complex problem we can face is that the way users perceive an operation as atomic is not the same as the application.

Imagine a scenario where we have a list of items, ordered by some criteria such as a date for example, and the system we are designing needs to allow the user to move items, the issue is that what from the user perspective is a single operation, a move, from the system perspective is a multiple operation, a move plus the update of all the other items to keep dates, for example, in sync.

In the above scenario a Undo() operation on the memento won't produce the expected result, unless we instruct the memento itself:

var memento = new ChangeTrackingService();

var person = new Person();
memento.Attach(person);

using(var op = memento.BeginAtomicOperation())
{
    person.FirstName = "a name";
    person.LastName = "last name";

    op.Complete();
}

At the end of the atomic operation, when Complete() is called, the state of the Person instance is changed but the stack contains one single change that, if undone, will revert back both the FirstName and LastName properties.

One important thing to keep in mind is that an atomic operation is not limited to a single object, multiple tracked instances can partecipate in the same atomic operation.

PreviousComplex objects graphNextChange Tracking Service API

Last updated 3 years ago