So in my code I have a list of items:-

        public List<IssueReceiveWorkOrderItemModel> IssueReceiveWorkOrderItems { get; set; } = new List<IssueReceiveWorkOrderItemModel>();

and it is being used in this code:-

 foreach (IssueReceiveWorkOrderItemModel item in IssueReceiveWorkOrderItems)
 {
     if (items.Any(o => !string.IsNullOrEmpty(o.Stock_Code)))
     {
         IssueReceiveWorkOrderItem issueReceiveWorkOrderItem = items.FirstOrDefault(o => o.Stock_Code.Equals(item.Stock_Code, StringComparison.CurrentCultureIgnoreCase));

         if (issueReceiveWorkOrderItem != null)
         {
             item.DifferenceQty = issueReceiveWorkOrderItem.Qty_Allocated - item.Qty_Allocated;
         }
     }
     else
     {
         item.DifferenceQty = -item.Qty_Allocated;
     }
 }

there were some issues after debugging I found out that the IssueReceiveWorkOrderItemModel item, is null when IssueReceiveWorkOrderItems has 3 items, the foreach loop is looping 3 times but the item is always null which is causing issue

I have checked my whole codebase there is no other duplicate for class IssueReceiveWorkOrderItemModel, this is my class:-

 public class IssueReceiveWorkOrderItemModel
 {
     public string Stock_Code { get; set; }
     public string Description { get; set; }
     public decimal? Qty_Allocated { get; set; }
     public decimal? DifferenceQty { get; set; }
 }

have anyone faced this type of issue before ?