Dependency Injection and IoC

Dependency Injection 
 How objects obtain dependent objects 
 The class being injected has no responsibillity in instantiating the object being injected
Key Theme: Avoid Tight Coupling 
 Types of Dependency Injection: 
 
 By class properties - not reccommended 
 By Setter 
 By Constructor - most perfered way 
 
 Inversion of Control 
 A technique to allow dependencies to be injected at runtime 
 IoC vs DI 
 
 DI is the composition of your classes 
 IoC is the runtime enviornment of your code