.ThenInclude in Specification Pattern , EF Core

Question

Can anybody please guide me, how to add .ThenInclude(s) in Specification pattern ; i am using Entity framework Core.

I have below code for .Include, which is working.

public interface ISpecification<T>
{
    Expression<Func<T, bool>> Criteria { get; }
    List<Expression<Func<T, object>>> Includes { get; }
}

public abstract class BaseSpecification<T> : ISpecification<T>
{
    protected BaseSpecification(Expression<Func<T, bool>> criteria)
    {
        Criteria = criteria;
    }
    public Expression<Func<T, bool>> Criteria { get; }
    public List<Expression<Func<T, object>>> Includes { get; } = new List<Expression<Func<T, object>>>();
    public List<string> IncludeStrings { get; } = new List<string>();

    protected virtual void AddInclude(Expression<Func<T, object>> includeExpression)
    {
        Includes.Add(includeExpression);
    }
}

}

Any help will be appreciated.

Answer 1

Found a solution to above problem. Below is the solution. Add in BaseSpecification class

protected virtual void AddInclude(string includeString)
{
    IncludeStrings.Add(includeString);
}

After that in Specification filter use like below for then include.

 AddInclude("Contacts.PrefixTitle");

This will include Contacts in Primary Class i.e. Account in my Case, then it includes Contacts then PrefixTitle