The document discusses inversion of control (IoC) and dependency injection (DI) using the Spring.NET framework. It defines IoC as inverting traditional control flow by responding to events rather than specifying procedures. DI is supplying external dependencies to components. Spring.NET is an IoC container that manages dependencies through configuration files defining objects and their properties. The document provides an example configuration and usage of Spring.NET to resolve dependencies between classes.

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2. Dependencies and Dependency Injection 10 May, 2009 2 Inversion Of Control - Spring.NET Overview

3. What is Dependency Injection? Dependency injection (DI) in programming refers to the process of supplying an external dependency to a software component. It is a specific form of inversion of control where the concern being inverted is the process of obtaining the needed dependency. 10 May, 2009 3 Inversion Of Control - Spring.NET Overview

4. But … what is Inversion of control? Inversion of control, or IoC, is an abstract principle describing an aspect of some software architecture designs in which the flow of control of a system is inverted in comparison to the traditional architecture. Control flow is expressed in imperative programming in the form of a series of instructions or procedure calls. Instead of specifying a sequence of decisions and procedures to occur during the lifetime of a process, the user of a IoCframework writes the desired responses linked to particular events or data requests. 10 May, 2009 4 Inversion Of Control - Spring.NET Overview

5. IOC Container 10 May, 2009 5 Inversion Of Control - Spring.NET Overview

6. Aha…and what is an IOC container? 10 May, 2009 6 Inversion Of Control - Spring.NET Overview

7. Spring.NET an application framework for buidling Enterprise .NET applications an IoC Container (Inversion of Control) that manages and injects dependencies on behalf of developers (DI = Dependency Injection) 10 May, 2009 Inversion Of Control - Spring.NET Overview 7

8. And more… 10 May, 2009 8 Inversion Of Control - Spring.NET Overview

9. IoC Containers for .NET PicoContainer.NET: lightweight and highly embeddable IoC container StructureMap: lightweight Inversion of Control (IoC) Container written in C#; can improve the architectural qualities of .NET apps by reducing the mechanical costs of good design techniques Castle: Tools for application development including small IoC container Spring.NET: full featured IoC container (port of Java version) 10 May, 2009 9 Inversion Of Control - Spring.NET Overview

10. Practice First approach - Dependencies public class ExampleObject { private AnotherObjectobjectOne; // dependencies private YetAnotherObjectobjectTwo; private inti; public AnotherObjectObjectOne { set { this.objectOne = value; } } public YetAnotherObjectObjectTwo { set { this.objectTwo = value; } } public intIntegerProperty { set { this.i = value; } } } 10 May, 2009 10 Inversion Of Control - Spring.NET Overview

11. Configuration I Preferred way to create Object Factories and Application contexts is via configuration: <configuration> <configSections> <sectionGroup name="spring"> <section name="context" type="Spring.Context.Support.ContextHandler, Spring.Core"/> <section name="objects" type="Spring.Context.Support.DefaultSectionHandler, Spring.Core" /> </sectionGroup> </configSections> <spring> <context> <resource uri="config://spring/objects"/> </context> <objects> ... </objects> </spring> </configuration> Handlers usedfor Spring configurationsection Where to find object configuration, e.g. file, assembly, config Configurationof Spring managedobjects 10 May, 2009 11 Inversion Of Control - Spring.NET Overview

12. Configuration II The configuration tells Spring.NET how objects depend on each other: Object name Object type: namespacepath + class, assembly <object id="exampleObject" type="Examples.ExampleObject, ExamplesLibrary"> <property name="objectOne" ref="anotherExampleObject"/> <property name="objectTwo" ref="yetAnotherObject"/> <property name="IntegerProperty" value="1"/> </object> <object id="anotherExampleObject" type="Examples.AnotherObject, ExamplesLibrary"/> <object id="yetAnotherObject" type="Examples.YetAnotherObject, ExamplesLibrary"/> Properties referring to other objects: often called dependencies or collaborators 10 May, 2009 12 Inversion Of Control - Spring.NET Overview

13. Usage Now instantiating an ApplicationContext is simple: ID that should appear in object configuration IApplicationContextctx = ContextRegistry.GetContext(); ExampleObject person = (ExampleObject)ctx.GetObject(“exampleObject "); 10 May, 2009 13 Inversion Of Control - Spring.NET Overview

14. Example application 10 May, 2009 14 Inversion Of Control - Spring.NET Overview

15. Solve the dependencies with Spring.NET IOC Demo 10 May, 2009 15 Inversion Of Control - Spring.NET Overview

16. 16 Inversion Of Control - Spring.NET Overview 10 May, 2009 http://en.wikipedia.org/wiki/Inversion_of_control http://martinfowler.com/articles/injection.html http://abdullin.com/wiki/inversion-of-control-ioc.html http://www.springframework.net/doc-latest/reference/html/objects.html http://www.developer.com/net/csharp/article.php/3722931/Dependency-Injection-with-SpringNet.htm Resources

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