C# Implementing Abstract factory pattern

Ive ABSTRACT FACTORY pattern in one of my projects: http://www.dofactory.com/Patterns/PatternAbstract.aspx


public class QuestaoResposta : QuestaoBaseResposta, IQuestao,IQuestionario
    public int IDQuestaoResposta { get; set; }

public class QuestaoFactory : QuestoesFactory
    public override QuestaoBaseResposta CreateQuestao()
        return new QuestaoResposta();

public abstract class QuestoesFactory
    public abstract QuestaoBaseResposta CreateQuestao();

public class QuestaoBaseResposta : IQuestao, IMarcas, IQuestionario
    // Constructor where i want to create a concrete instance 
    // of any class that inherits QuestaoBaseResposta using QuestoesFactory 
    // abstract class, and assign it to current instance of
    // QuestaoBaseResposta class
    public QuestaoBaseResposta(QuestoesFactory qf)
        this = qf.CreateQuestao();

Problem is that i cant assing a value to current class using "THIS" keyword.


QuestaoBaseResposta qs = new QuestaoBaseResposta(new QuestaoFactory());

// Here i want the qs intance to be type of QuestaoResposta
// since im passing QuestaoFactory as argument,without cast anything.
qs.IDQuestaoResposta = 0;

What would you suggest to cast the QuestaoBaseResposta class to the inherit type (QuestaoResposta),without cast?


No you can't cast without cast. The usefulness of a factory comes from the fact that xyou do not need to know the exact derived class of the returned object. This is different if you donÄt use a factory but instead calling a constructor where you know the exact type.

Why don't you do it this way:

QuestaoBaseResposta qs = new QuestaoFactory().CreateQuestao();

this is readonly. So you cannot assign to it.

Need Your Help

Generating Interfaces from entity framework database first auto-generated code

c# entity-framework separation-of-concerns

I am using MVC3, C# 4.0 and Entity Framework in Visual Studio 2010. I am generating my edmx and Designed.cs files from a database. I am then generating interfaces from the entities in the Designer.cs

Getting a Jetty exception when I reloading my GWT development web server

java gwt jetty

I'm getting this exception when restarting my GWT server. I can't find any information on this exception that pertains to a server reload. The exception doesn't seem to cause any problems but it's

About UNIX Resources Network

Original, collect and organize Developers related documents, information and materials, contains jQuery, Html, CSS, MySQL, .NET, ASP.NET, SQL, objective-c, iPhone, Ruby on Rails, C, SQL Server, Ruby, Arrays, Regex, ASP.NET MVC, WPF, XML, Ajax, DataBase, and so on.