...

Back/Services/ServCOD.cs

@@ -170,5 +170,9 @@ namespace Back.Services
 
             }
         }
+        public async Task<bool> UsedInTheInvoice(int codID)
+        {
+            return await _CODRepo.Get(w => w.invoiceDetails.Any(a=>a.CODID==codID)).AnyAsync();
+        }
     }
 }

Back/Services/servCustomer.cs

@@ -9,12 +9,13 @@ namespace Back.Services
     public class servCustomer
     {
         private readonly IAsyncRepository<Customer> _repoCus;
+        private readonly IAsyncRepository<Invoice> _repoInvoice;
         private readonly CheckPermission _checkPermission;
-        public servCustomer(IAsyncRepository<Customer> repoCus, CheckPermission checkPermission)
+        public servCustomer(IAsyncRepository<Customer> repoCus, CheckPermission checkPermission, IAsyncRepository<Invoice> repoInvoice)
         {
            _repoCus = repoCus;
             _checkPermission = checkPermission;
-
+            _repoInvoice = repoInvoice;
         }
         public async Task<PagingDto<RCustomer>?> GetCustomers(int CompanyID, ItemSerchGetCustomer itemSerch)
         {
@@ -189,6 +190,10 @@ namespace Back.Services
 
             }
         }
+        public async Task<bool> UsedInTheInvoice(int cusID)
+        {
+            return await _repoInvoice.Get(w => w.CustomerID == cusID).AnyAsync();
+        }
 
 
     }

Back/Services/servInvoice.cs

@@ -125,6 +125,9 @@ namespace Back.Services
 
             if (itemSerch.refInvoiceID != null)
                 invok = invok.Where(w => w.BillReference==itemSerch.refInvoiceID);
+
+            if(itemSerch.CodID != null)
+                invok = invok.Where(w => w.invoiceDetails.Any(wa=>wa.CODID== itemSerch.CodID));
             //foreach (InputObj item in inputObjs)
             //    invok = invok.Where(ExMethod.GetFunc<Customer>(item.Param, item.Value));