diff --git a/Controller/SCP_INVOICE_CONTROLLER.cs b/Controller/SCP_INVOICE_CONTROLLER.cs
index afa8453..20ea900 100644
--- a/Controller/SCP_INVOICE_CONTROLLER.cs
+++ b/Controller/SCP_INVOICE_CONTROLLER.cs
@@ -497,11 +497,11 @@ namespace CK.SCP.Controller
                     {
                         q = q.Where(p => p.VendName.Contains(p_entity.VendName));
                     }
-                    if (p_entity.BeginTime != null && !p_entity.BeginTime.ToString().Contains("0001/1/1"))
+                    if (p_entity.BeginTime != null && !p_entity.BeginTime.ToString("yyyy-M-d").Contains("0001-1-1"))
                     {
                         q = q.Where(p => p.CreateTime >= p_entity.BeginTime);
                     }
-                    if (p_entity.EndTime != null && !p_entity.EndTime.ToString().Contains("0001/1/1"))
+                    if (p_entity.EndTime != null && !p_entity.EndTime.ToString("yyyy-M-d").Contains("0001-1-1"))
                     {
                         q = q.Where(p => p.CreateTime <= p_entity.EndTime);
                     }