Command, CommandHandler and CommandInvoker

Take a look at this article: Meanwhile… on the command side of my architecture

It contains a thorough explanation about why you want to use commands and command handlers as part of your architecture. An architectural pattern such as CQRS is based on commands and events, but even without applying CQRS, the use of commands in your architecture is very valuable, as the article explains.

The RavenGallery project, however, is too small to really see the benefits of this command/handler model. This model starts to shine when a project gets bigger.

A more thorough discussion on this topic can be found in chapter 10 of my book.