Questions tagged [postsharp]

With PostSharp, you can easily write and apply custom attributes that add new behaviors to your code - tracing, thread management, exception handling, data binding, and much more.

PostSharp works by injecting IL during the build process to weave aspects into the original method.

Ready-made patterns

PostSharp comes with a library of ready-made pattern implementations including code contracts, INotifyPropertyChanged, immutable, freezable and other threading models.

Example: the following snippet shows how the NotifyPropertyChanged attribute automatically implementes the INotifyPropertyChanged interface, including listening to two levels of child objects.

[NotifyPropertyChanged]
public class CustomerViewModel
{
    public CustomerModel Customer { get; set; }

    public string FullName
    {
        get
        {
            if (Customer == null) return null;

            return string.Format("{0} {1} from {2}",
                Customer.FirstName,
                Customer.LastName,
                Customer.PrincipalAddress != null ? 
                  Customer.PrincipalAddress.FullAddress : "?");
        }
    }
}

Custom patterns

PostSharp also has a rich toolkit to automate the implementation of your own patterns.

Examples:

Tracing:

[PSerializable]
public class TraceAttribute : OnMethodBoundaryAspect
{
  public override void OnEntry(MethodExecutionEventArgs eventArgs)
  { 
     Trace.TraceInformation("Entering {0}.", eventArgs.Method); 
  }

  public override void OnExit(MethodExecutionEventArgs eventArgs)
  { 
     Trace.TraceInformation("Leaving {0}.", eventArgs.Method); }
  }
}

Thread dispatch WPF:

[PSerializable]
public class GuiThreadAttribute : OnMethodInvocationAspect
{
   public override void OnInvocation(MethodInvocationEventArgs eventArgs)
   {
       DispatcherObject dispatcherObject = (DispatcherObject)eventArgs.Delegate.Target;
       if (dispatcherObject.CheckAccess())
           eventArgs.Proceed();
       else
           dispatcherObject.Dispatcher.Invoke(DispatcherPriority.Normal,
                                               new Action(() => eventArgs.Proceed()));
   }
}

Usage:

[Trace]
public void CreateCustomer(int id, string name) { /* ... */ }

Installation

PostSharp can most easily be installed through its NuGet package.

Install-Package PostSharp

Licensing

PostSharp is a commercial product with a free edition.