Entity framework with business layer and data access layer

Abhilash J A

Hello Everyone,

I have model.edmx file, DataAccessLayer, BussinessLayer and MVC. I have done DAL layer .dll referred inside BAL layer. How can I connect with each other without using AUTOMAPPER ?

DAL,

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using DAL.Model;
namespace DAL
{
public class ProductCategoryDAL
{
public List SelectAccessHistory(int idAccessHistory)
{
using (var context = new REBOXEntities())
{
if (idAccessHistory > 0)
return context.AccessHistories.Where(s => s.idAccessHistory == idAccessHistory).ToList();
else
return context.AccessHistories.ToList();
}
}
}
}

BAL,

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using DAL;
using DAL.Model;
namespace BAL
{
public class ProductCategoryBAL
{
ProductCategoryDAL productCategoryDAL = new ProductCategoryDAL();
public List SelectAccessHistory(int idAccessHistory)
{
try
{
List < BAL.Model.AccessHistory > objBALAccessHistory = productCategoryDAL.SelectAccessHistory(idAccessHistory).ToList(); /*Here occuring error*/
return objBALAccessHistory;
}
catch (Exception ee)
{
throw ee;
}
}
}
}

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Chetan Ranpariya9y ago
Accepted answer
Hi Abhilash,

You can not directly cast your DAL Model class to BAL model class.

You have to write a conversion Logic where you Convert DAL Model to BAL model.

Following might help you.
You can create a constructor of you BAL Model class as following.
public class AccessHistory
{
    public AccessHistory(DAL.Model.AccessHistory dalAccessHistory)
    {
        //Code to set properties from dalAccessHistory.
        this.Property1 = dalAccessHistory.Property1;
        //So On..
    }
}
And then use it to convert the DAL Model objects coming from DAL to the BAL Model Objects. as following.
public class ProductCategoryBAL
{
    ProductCategoryDAL productCategoryDAL = new ProductCategoryDAL();

    public List SelectAccessHistory(int idAccessHistory)
    {
        var balObjectHistoryList = new List();
        try
        {
            List dalAccessHistoryList = productCategoryDAL.SelectAccessHistory(idAccessHistory);

            foreach(var dalObject in dalAccessHistoryList)
            {
                var balAccessHistory = new BAL.Model.AccessHistory(dalObject);

                balObjectHistoryList.Add(balAccessHistory);
            }
            return balObjectHistoryList;
        }
        catch (Exception ee)
        {
            throw ee;
        }
    }
}
I hope this will resolve the issue you are facing.
Alternatively you can create a separate layer where you write conversion logic from BAL Model to DAL Model and vice versa and call it from you BAL when you retrive data from DAL or you want to save data to DAL.

Thanks and regards,
Chetan Ranpariya
Abhilash J A9y ago
Hello,

Tapan and Chetan very thank you for advice me.

@Chetan, What is you mean by create a separate layer? with respect to this get list method, could you please give an example for that separate layer? I am using entity framework shema first approach to access sql server database.
Tapan Patel9y ago
The errors must be due to casting entity type object to business type of object - where compiler has no way to identify what is the type of objects or how to convert one to another.

If you are going away from the automapper then you may want to write your own method (kind of conversion methods) in BAL that converts your entity objects to business & vice-a-versa.
Chetan Ranpariya9y ago
What type of error you are getting?