c# ,Get Generic Type Property from Abstract Factory Classes

Question

I am implementing the abstract factory pattern to create a dynamic Matrix DataTable. The idea is create different generator instance base on a factory class. However, at the end of the structure, i wish to obtain the end result as an object that would going to expose to the MVC View. The problem is I cant think of a way to extract the output because the generator instance bear with generic attribute. My code is like this :

Enum and Generic Classes

public enum GeneratorType
    {
        GenericBudgetGenerator = 1
    }


public class GenericMatrix<T>
{
    public List<string> MatrixHeaders { set; get; }
    public List<T> MatrixRow { set; get; }
    public T MatrixFooterRow { set; get; }
}

public class GenericItemRow
    {
        public string EntityName { set; get; }
        public List<double> Values { set; get; }
        public double Total { set; get; }

    }

Generator and Interface

public interface IGenerator
    {
        void Build();
    }

public interface IMatrixGenerator<TRow>
        : IGenerator
    {
        IEnumerable<TRow> CreateCellValues();
    }

public class MatrixGeneratorFactory
{
    public static IGenerator Create(Enum _type)
    {
        switch (_type)
        {
            case GeneratorType.GenericGenerator :
                return new GenericGenerator ();
            default:
                throw new ArgumentException("No generator exist");
        }
    }
}

public class MatrixGeneratorBase
{         
            public void BuildMatrixTemplate()
        {
              //some logic
         }

}

public class GenericGenerator : MatrixGeneratorBase, IMatrixGenerator<GenericItemRow>
{

        public IEnumerable<GenericItemRow> CreateCellValues()
        {
              //some logic here
         }

        public void Build()
        {
             BuildMatrixTemplate();

             GenericMatrix<GenericBudgetValueMatrixRow> _genericMatrix = new GenericMatrix<GenericBudgetValueMatrixRow>();

              _genericMatrix = //Some logic here
         }

}

Client Code

 class Program
 {
    static void Main(string[] args)
    {
       IGenerator generator = MatrixGeneratorFactory.Create(GeneratorType.GenericGenerator );
       generator.Build();

     //How can i get the _genericMatrix out from the generator instance

     }
 }

Since the _genericMatrix is a strong typed property in the GenericGenerator, i cant find a way to retrieve it back with the IGenerator.

Answer 1

You need to create public property for this. As there is no way you can access private variable using object of any class.

Answer 2

I suppose, Build should return the created matrix, so it becomes

public interface IGenerator
{
    object Build();
}

and

public class GenericGenerator : MatrixGeneratorBase, IMatrixGenerator<GenericItemRow>
{
    public object Build()
    {
         BuildMatrixTemplate();

         var genericMatrix = new GenericMatrix<GenericBudgetValueMatrixRow>();

         genericMatrix = //Some logic here

         return genericMatrix;
     }

}

Answer 3

Like Haukinger said: return the genericMatrix would be the simplest way, but I would define the Generator generic too, because you would want to build different Matrices. So you can do this:

public interface IGenerator
{
    IMatrix Build();
}

public class GenericGenerator<TRow> : MatrixGeneratorBase, 
IMatrixGenerator<GenericItemRow> where TRow : GenericItemRow
{

        public IEnumerable<GenericItemRow> CreateCellValues()
    {
          //some logic here
    }

    public IMatrix Build()
    {
         BuildMatrixTemplate();

         GenericMatrix<TRow> _genericMatrix = new 
         GenericMatrix<TRow>();

          _genericMatrix = //Some logic here
          return _genericMatrix;

     }

}

public interface IMatrix
{
  //Properties that you need to use.
}

public class GenericMatrix<T> : IMatrix  where T : GenericItemRow
{
    public List<string> MatrixHeaders { set; get; }
    public List<T> MatrixRow { set; get; }
    public T MatrixFooterRow { set; get; }
}