public class BaseModelFactory<TEntity, TContext>
        where TEntity : class,IEntry, new()
        where TContext : DbContext, new()
    {
        string _connectionstring;
        DbContext _context;
        AsyncCallback _callback;

public BindingList<TEntity> GetSqlQueryData(bool addemptyrow, string sqltext, params object[] args)
        {
            _newitem = null;
            try
            {
                if (BaseContext != null)
                {
                    BaseContext.Dispose();
                    BaseContext = null;
                }
                BaseContext.Database.Connection.ConnectionString = _connectionstring;
                BaseContext.Set<TEntity>().SqlQuery(sqltext, args).ToList<TEntity>();
                if (addemptyrow)
                    AddNewItem(args);
                return BaseContext.Set<TEntity>().Local.ToBindingList();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                return null;
            }
        }

DbContext BaseContext
        {
            get
            {
                if (_context == null) _context = new TContext();
                return _context;
            }
            set
            {
                _context = value;
            }
        }