src/Hotline.Share/Dtos/Order/OrderDto.cs

@@ -150,7 +150,7 @@ namespace Hotline.Share.Dtos.Order
         /// <returns></returns>
         public string GetAllDurationHour()
         {
-            if (CreationTimeHandleDurationWorkday > 0)
+            if (CreationTimeHandleDurationWorkday != null && CreationTimeHandleDurationWorkday > 0)
             {
                 return Math.Round(Math.Round(CreationTimeHandleDurationWorkday.Value) / 60 / 60, 2).ToString() + "";
             }