How can I join two unrelated table in a SelectList?

Question

I have two unrelated tables and I want to join PTWTypeName from first table and PTWTypeNameOrg from the second one into a SelectList.

 

public class PTWType
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public string PTWId { get; set; }
        public string PTWTypeName { get; set; }
    }
    public class PTWTypeOrg
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public string PTWIdOrg { get; set; }
        public string PTWTypeNameOrg { get; set; }
        public string OrgID { get; set; }
    }

 What I tried is

 

var ptwType = await _context.PTWTypesOrg
                                 .Join(_context.PTWTypes, t1 => t1.PTWTypeNameOrg, t2 => t2.PTWTypeName, (t1, t2) => new
                                 {
                                     PTW1 = t1.PTWTypeNameOrg,
                                     PTW2 = t2.PTWTypeName,
                                 }).ToListAsync();

            PTWTypeSL = new SelectList(ptwType);

but no result in the SelectList