new flowNo to use id if deskcustomer's toFlowNo is null

Model/wms/tables/WmsDeskCustomer.cs

@@ -68,6 +68,15 @@ namespace DeiNiu.wms.Data.Model
             else
                 return CustOper(201);
         }
+
+        public   string toFlowNo
+        {
+            get
+            {
+                return string.IsNullOrEmpty(_flowNo)?_id+"":_flowNo;
+
+            }
+        }
     }
 }