AOP with PostSharp

PostSharp is a great open-source tool that allows you to encapsulate the non-business logic in custom attributes. That’s the Aspect Oriented Programming paradigm main goal: the separation of concerns.

This tool heps you to free the business logic from the infrastructure code such as:

• Transactions
• Logging
• Permissions / Security
• Exceptions handling
• Caching
• Settings

Your code will be cleaner than never.

…and why do I call it a “great tool”? Because, unlike other tools that uses reflection and other techniques that reduces performance, PostSharp works at MSIL level!. It generates MSIL code to be injected in your code at compilation time, in that way it supports any .NET language and get the best performance possible.

Furthermore, this tool is really easy to learn. You can quickly get started by using the basic features, follow this simple quick start:

• PostSharp – QuickStart

The following example shows a simple PostSharp aspect to trace the execution of the methods marked with that attribute:

public class SimplestTraceAttribute : OnMethodBoundaryAspect
{
public override void OnEntry( MethodExecutionEventArgs eventArgs)
{
Trace.TraceInformation(“Entering {0}.”, eventArgs.Method);
Trace.Indent();
}
public override void OnExit( MethodExecutionEventArgs eventArgs)
{
Trace.Unindent();
Trace.TraceInformation(“Leaving {0}.”, eventArgs.Method);
}
}

…and it works like a charm!

The evidence:

Building the project:

Inspecting the binaries:

Results:

Resources:

• PostSharp Official WebSite (see About PostSharp)
• Visual Basic PostSharp Samples

Enjoy it!

Tags: .NET, AOP, PostSharp