working with Entity Framework ntier - convert list to icollection error

Question

Below is what I am trying to do. I am using Entity Framework 6 and I have a DataLayer Object that I am passing up the layers to a BusinessData Object. Basically get the object from the database and pass its values to a new object that mirrors it in the BusinessData layer.

See below for code.

Entity Framework Generated Object

public partial class SolutionArea
    {
        public SolutionArea()
        {
            this.Awards = new HashSet<Award>();
            this.Competencies = new HashSet<Competency>();
            this.KeyWins = new HashSet<KeyWin>();
            this.Offerings = new HashSet<Offering>();
            this.Products = new HashSet<Product>();
            this.Programs = new HashSet<Program>();
        }

        public int ID { get; set; }
        public string Title { get; set; }
        public string Description { get; set; }
        public string Manager { get; set; }
        public string PreSalesCount { get; set; }

        public virtual ICollection<Award> Awards { get; set; }
        public virtual ICollection<Competency> Competencies { get; set; }
        public virtual ICollection<KeyWin> KeyWins { get; set; }
        public virtual ICollection<Offering> Offerings { get; set; }
        public virtual ICollection<Product> Products { get; set; }
        public virtual ICollection<Program> Programs { get; set; }
    }

Data Layer Object

namespace SolutionsEntities.DataAccessObjects
{
    public class SolutionAreaDAO
    {
        public SolutionAreaBDO GetSolutionArea(int Id)
        {
            SolutionAreaBDO solutionAreaBDO = null;
            using(var context = new SolutionsEntities())
            {
                SolutionArea solutionAreaDAO = (from s in context.SolutionAreas
                                            where s.ID == Id
                                            select s).FirstOrDefault();
                if (solutionAreaDAO != null)
                {
                    solutionAreaBDO = new SolutionAreaBDO();
                    {
                        solutionAreaBDO.Title = solutionAreaDAO.Title;
                        solutionAreaBDO.Programs = solutionAreaDAO.Programs;  
                    }
                }

            }
        }
    }

Business Data Object

    namespace SolutionsBDO
{
    public class SolutionAreaBDO
    {
        public int ID { get; set; }
        public string Title { get; set; }
        public string Description { get; set; }
        public string Manager { get; set; }
        public string PreSalesCount { get; set; }
        public virtual ICollection<AwardBDO> Awards { get; set; }
        public virtual ICollection<CompetencyBDO> Competencies { get; set; }
        public virtual ICollection<KeyWinBDO> KeyWins { get; set; }
        public virtual ICollection<OfferingBDO> Offerings { get; set; }
        public virtual ICollection<ProductBDO> Products { get; set; }
        public virtual ICollection<ProgramBDO> Programs { get; set; }

    }
}

The problem I have is in the SolutionAreaDAO class above I get an Error saying I cannot convert an ICollection to an ICollection. This is the line of code that causes the issue:

solutionAreaBDO = new SolutionAreaBDO();
                        {
                            solutionAreaBDO.Title = solutionAreaDAO.Title;
                            solutionAreaBDO.Programs = solutionAreaDAO.Programs;  
                        }

Both objects have a property that is a separate entity. SolutionArea object contains a Collection of Program objects. When I try to set the collection from the Data Object to the Business Object I get an explicit cast error.

Error      1              Cannot implicitly convert type 'System.Collections.Generic.ICollection<SolutionsEntities.Program>' to 'System.Collections.Generic.ICollection<SolutionsBDO.ProgramBDO>'. An explicit conversion exists (are you missing a cast?) C:\Projects\SolutionsBackgrounder\SolutionsEntities\DataAccessObjects\SolutionAreaDAO.cs 26                52           SolutionsEntities

I'm sure I'm just not doing tis right but if someone can point me in the right direction it would be much appreciated!

Thanks,

Joe

Answer 1

You're trying to convert a ICollection<SolutionsEntities.Program>> to an ICollection<SolutionsBDO.ProgramBDO>

Those are two collections with a different type parameter (that are unrelated as far as the compiler is concerned). You need to either convert these objects manually, change the collection type on either you BDO or your DAO or use something like AutoMapper to convert them automatically