Реализовал хранение писем в файлах

SecuritySystem/SecuritySystemFileImplement/DataFileSingleton.cs

@@ -11,11 +11,13 @@ namespace SecuritySystemFileImplement
         private readonly string SecureFileName = "Secure.xml";
         private readonly string ClientFileName = "Client.xml";
         private readonly string ImplementerFileName = "Implementer.xml";
+        private readonly string MessageInfoFileName = "MessageInfo.xml";
         public List<Component> Components { get; private set; }
         public List<Order> Orders { get; private set; }
         public List<Secure> Secures { get; private set; }
         public List<Client> Clients { get; private set; }
         public List<Implementer> Implementers { get; private set; }
+        public List<MessageInfo> MessageInfos { get; private set; }
         public static DataFileSingleton GetInstance()
         {
             if (instance == null)
@@ -29,6 +31,7 @@ namespace SecuritySystemFileImplement
         public void SaveOrders() => SaveData(Orders, OrderFileName, "Orders", x => x.GetXElement);
         public void SaveClients() => SaveData(Clients, ClientFileName, "Clients", x => x.GetXElement);
         public void SaveImplementers() => SaveData(Implementers, ImplementerFileName, "Implementers", x => x.GetXElement);
+        public void SaveMessageInfos() => SaveData(MessageInfos, MessageInfoFileName, "MessageInfos", x => x.GetXElement);
         private DataFileSingleton()
         {
             Components = LoadData(ComponentFileName, "Component", x => Component.Create(x)!)!;
@@ -36,6 +39,7 @@ namespace SecuritySystemFileImplement
             Orders = LoadData(OrderFileName, "Order", x => Order.Create(x)!)!;
             Clients = LoadData(ClientFileName, "Client", x => Client.Create(x)!)!;
             Implementers = LoadData(ImplementerFileName, "Implementer", x => Implementer.Create(x)!)!;
+            MessageInfos = LoadData(MessageInfoFileName, "MessageInfo", x => MessageInfo.Create(x)!)!;
         }
         private static List<T>? LoadData<T>(string filename, string xmlNodeName, Func<XElement, T> selectFunction)
         {

SecuritySystem/SecuritySystemFileImplement/Implements/MessageInfoStorage.cs

@@ -0,0 +1,53 @@
+using SecuritySystemContracts.BindingModels;
+using SecuritySystemContracts.SearchModels;
+using SecuritySystemContracts.StoragesContracts;
+using SecuritySystemContracts.ViewModels;
+using SecuritySystemFileImplement.Models;
+
+namespace SecuritySystemFileImplement.Implements
+{
+    public class MessageInfoStorage : IMessageInfoStorage
+    {
+        private DataFileSingleton _source;
+        public MessageInfoStorage()
+        {
+            _source = DataFileSingleton.GetInstance();
+        }
+
+        public MessageInfoViewModel? GetElement(MessageInfoSearchModel model)
+        {
+            return GetFilteredList(model).FirstOrDefault();
+        }
+
+        public List<MessageInfoViewModel> GetFilteredList(MessageInfoSearchModel model)
+        {
+            var messageInfos = GetFullList();
+            if (!string.IsNullOrEmpty(model.MessageId))
+            {
+                messageInfos = messageInfos.Where(x => x.MessageId == model.MessageId).ToList();
+            }
+            if (model.ClientId != null)
+            {
+                messageInfos = messageInfos.Where(x => x.ClientId == model.ClientId).ToList();
+            }
+            return messageInfos;
+        }
+
+        public List<MessageInfoViewModel> GetFullList()
+        {
+            return _source.MessageInfos.Select(x => x.GetViewModel).ToList();
+        }
+
+        public MessageInfoViewModel? Insert(MessageInfoBindingModel model)
+        {
+            var messageInfo = MessageInfo.Create(model);
+            if (messageInfo == null)
+            {
+                return null;
+            }
+            _source.MessageInfos.Add(messageInfo);
+            _source.SaveMessageInfos();
+            return messageInfo.GetViewModel;
+        }
+    }
+}

SecuritySystem/SecuritySystemFileImplement/Models/MessageInfo.cs

@@ -0,0 +1,81 @@
+using SecuritySystemContracts.BindingModels;
+using SecuritySystemContracts.ViewModels;
+using SecuritySystemDataModels.Models;
+using System.Reflection;
+using System.Xml.Linq;
+
+namespace SecuritySystemFileImplement.Models
+{
+    public class MessageInfo : IMessageInfoModel
+    {
+        public string MessageId { get; set; } = string.Empty;
+        public int? ClientId { get; set; }
+        public string SenderName { get; set; } = string.Empty;
+        public DateTime DateDelivery { get; set; } = DateTime.Now;
+        public string Subject { get; set; } = string.Empty;
+        public string Body { get; set; } = string.Empty;
+
+        public static MessageInfo? Create(MessageInfoBindingModel model)
+        {
+            if (model == null)
+            {
+                return null;
+            }
+            return new MessageInfo()
+            {
+                MessageId = model.MessageId,
+                ClientId = model.ClientId,
+                SenderName = model.SenderName,
+                DateDelivery = model.DateDelivery,
+                Subject = model.Subject,
+                Body = model.Body,
+            };
+        }
+        public static MessageInfo? Create(XElement element)
+        {
+            if (element == null)
+            {
+                return null;
+            }
+            return new MessageInfo()
+            {
+                MessageId = element.Attribute("MessageId")!.Value,
+                ClientId = Convert.ToInt32(element.Element("ClientId")!.Value),
+                SenderName = element.Element("SenderName")!.Value,
+                DateDelivery = Convert.ToDateTime(element.Element("DateDelivery")!.Value),
+                Subject = element.Element("Subject")!.Value,
+                Body = element.Element("Body")!.Value,
+            };
+        }
+        public void Update(MessageInfoBindingModel model)
+        {
+            if (model == null)
+            {
+                return;
+            }
+            MessageId = model.MessageId;
+            ClientId = model.ClientId;
+            SenderName = model.SenderName;
+            DateDelivery = model.DateDelivery;
+            Subject = model.Subject;
+            Body = model.Body;
+        }
+        public MessageInfoViewModel GetViewModel => new()
+        {
+            MessageId = MessageId,
+            ClientId = ClientId,
+            SenderName = SenderName,
+            DateDelivery = DateDelivery,
+            Subject = Subject,
+            Body = Body,
+        };
+        public XElement GetXElement => new("MessageInfo",
+            new XAttribute("MessageId", MessageId),
+            new XElement("ClientId", ClientId.ToString()),
+            new XElement("SenderName", SenderName),
+            new XElement("DateDelivery", DateDelivery.ToString()),
+            new XElement("Subject", Subject),
+            new XElement("Body", Body)
+        );
+    }
+}