public IHttpActionResult AssigningDevices(DeviceandUsersModel model)
 {
     try
     {
         if (ModelState.IsValid)
         {
             var validdevice = db.DevicePasswords.Where(s => s.DeviceId == model.DeviceId).ToList();
             var validuser   = db.Users.Where(s => s.UserId == model.UserId).ToList();
             //var chkexists = db.DeviceforUsers.Where(s => s.DeviceId==model.DeviceId || s.UserId==model.UserId).ToList();
             if ((validdevice.Count != 0) && (validuser.Count != 0))
             {
                 var adddeviceusers = new DeviceforUser();
                 adddeviceusers.DeviceId  = model.DeviceId;
                 adddeviceusers.UserId    = model.UserId;
                 adddeviceusers.FirstName = model.FirstName;
                 db.DeviceforUsers.Add(adddeviceusers);
                 db.SaveChanges();
                 return(Ok(adddeviceusers));
             }
             else if (validdevice.Count == 0)
             {
                 return(Ok("Device Not Exists"));
             }
             else if (validuser.Count == 0)
             {
                 return(Ok("User Not Exists"));
             }
             else
             {
                 return(NotFound());
             }
         }
         else
         {
             return(Ok("Please Enter All the mandatory Fields"));
         }
     }
     catch (Exception ex)
     {
         return(NotFound());
     }
 }
 public IHttpActionResult RevokeAssigningDevices(DeviceandUsersModel model)
 {
     try
     {
         var validdevice = db.DevicePasswords.Where(s => s.DeviceId == model.DeviceId).ToList();
         var validuser   = db.Users.Where(s => s.UserId == model.UserId).ToList();
         var device      = db.DeviceforUsers.Where(s => s.DeviceId == model.DeviceId).FirstOrDefault();
         if ((validdevice.Count != 0) && (validuser.Count != 0) && (device != null))
         {
             device.UserId    = model.UserId;
             device.FirstName = model.FirstName;
             db.SaveChanges();
             return(Ok(device));
         }
         else if (validdevice.Count == 0)
         {
             return(Ok("Device Not Exists"));
         }
         else if (validuser.Count == 0)
         {
             return(Ok("User Not Exists"));
         }
         else if (device == null)
         {
             return(Ok("The device till not assigned. Need to assign first."));
         }
         else
         {
             return(NotFound());
         }
     }
     catch (Exception ex)
     {
         return(NotFound());
     }
 }