ломаем

ComputersShop/ComputersShopBusinessLogic/MailWorker/AbstractMailWorker.cs

@@ -19,6 +19,7 @@ namespace ComputersShopBusinessLogic.MailWorker
         protected string _popHost = string.Empty;
         protected int _popPort;
         private readonly IMessageInfoLogic _messageInfoLogic;
+        private readonly IClientLogic _clientLogic;
         private readonly ILogger _logger;
         public AbstractMailWorker(ILogger<AbstractMailWorker> logger, IMessageInfoLogic messageInfoLogic)
         {
@@ -75,6 +76,7 @@ namespace ComputersShopBusinessLogic.MailWorker
             _logger.LogDebug("Check Mail: {Count} new mails", list.Count);
             foreach (var mail in list)
             {
+                mail.ClientId = _clientLogic.ReadElement(new() { Email = mail.SenderName })?.Id;
                 _messageInfoLogic.Create(mail);
             }
         }

ComputersShop/ComputersShopView/DataGridViewExtension.cs

@@ -26,7 +26,6 @@ namespace ComputersShopView
                 {
                     throw new InvalidOperationException($"Не найден атрибут типа ColumnAttribute для свойства {property.Name}");
                 }
-                // ищем нужный нам атрибут
                 if (attribute is ColumnAttribute columnAttr)
                 {
                     column.HeaderText = columnAttr.Title;