4 пункт?

Shipyard/ShipyardContracts/StoragesContracts/IMessageInfoStorage.cs

@@ -18,5 +18,7 @@ namespace ShipyardContracts.StoragesContracts
         MessageInfoViewModel? GetElement(MessageInfoSearchModel model);
 
         MessageInfoViewModel? Insert(MessageInfoBindingModel model);
+
+        MessageInfoViewModel? Update(MessageInfoBindingModel model);
     }
 }

Shipyard/ShipyardContracts/ViewModels/MessageInfoViewModel.cs

@@ -27,9 +27,9 @@ namespace ShipyardContracts.ViewModels
         public string Body { get; set; } = string.Empty;
 
         [DisplayName("Прочитано")]
-        public bool IsRead { get; private set; } = false;
+        public bool IsRead { get; set; } = false;
 
         [DisplayName("Ответ")]
-        public string? AnswerText { get; private set; }
+        public string? AnswerText { get; set; } = string.Empty;
     }
 }

Shipyard/ShipyardDataBaseImplement/Implements/MessageInfoStorage.cs

@@ -66,5 +66,19 @@ namespace ShipyardDataBaseImplement.Implements
             context.SaveChanges();
             return newMessage.GetViewModel;
         }
+
+        public MessageInfoViewModel? Update(MessageInfoBindingModel model)
+        {
+            using var context = new ShipyardDataBase();
+            var message = context.Messages.FirstOrDefault(x => x.MessageId ==
+           model.MessageId);
+            if (message == null)
+            {
+                return null;
+            }
+            message.Update(model);
+            context.SaveChanges();
+            return message.GetViewModel;
+        }
     }
 }

Shipyard/ShipyardDataBaseImplement/Models/Message.cs

@@ -4,6 +4,7 @@ using ShipyardDataModels.Models;
 using System;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
+using System.Diagnostics;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
@@ -45,6 +46,11 @@ namespace ShipyardDataBaseImplement.Models
             };
         }
 
+        public void Update(MessageInfoBindingModel model)
+        {
+            IsRead = model.IsRead;
+            AnswerText = model.AnswerText;
+        }
         public MessageInfoViewModel GetViewModel => new()
         {
             Body = Body,
@@ -53,6 +59,8 @@ namespace ShipyardDataBaseImplement.Models
             MessageId = MessageId,
             SenderName = SenderName,
             DateDelivery = DateDelivery,
+            IsRead=IsRead,
+            AnswerText=AnswerText
         };
     }
 }

Shipyard/ShipyardFileImplement/Implements/MessageInfoStorage.cs

@@ -54,5 +54,17 @@ namespace ShipyardFileImplement.Implements
             source.SaveMessages();
             return newMessage.GetViewModel;
         }
+
+        public MessageInfoViewModel? Update(MessageInfoBindingModel model)
+        {
+            var message = source.Messages.FirstOrDefault(x => x.MessageId == model.MessageId);
+            if (message == null)
+            {
+                return null;
+            }
+            message.Update(model);
+            source.SaveImplementers();
+            return message.GetViewModel;
+        }
     }
 }

Shipyard/ShipyardFileImplement/Models/Message.cs

@@ -59,6 +59,15 @@ namespace ShipyardFileImplement.Models
             };
         }
 
+        public void Update(MessageInfoBindingModel model)
+        {
+            if (model == null)
+            {
+                return;
+            }
+            IsRead = model.IsRead;
+            AnswerText = model.AnswerText;
+        }
         public MessageInfoViewModel GetViewModel => new()
         {
             Body = Body,
@@ -66,7 +75,9 @@ namespace ShipyardFileImplement.Models
             DateDelivery = DateDelivery,
             SenderName = SenderName,
             ClientId = ClientId,
-            MessageId = MessageId
+            MessageId = MessageId,
+            IsRead=IsRead,
+            AnswerText=AnswerText
         };
 
         public XElement GetXElement => new("MessageInfo",
@@ -75,7 +86,9 @@ namespace ShipyardFileImplement.Models
             new XAttribute("ClientId", ClientId),
             new XAttribute("MessageId", MessageId),
             new XAttribute("SenderName", SenderName),
-            new XAttribute("DateDelivery", DateDelivery)
+            new XAttribute("DateDelivery", DateDelivery),
+            new XAttribute("IsRead", IsRead),
+            new XAttribute("AnswerText", AnswerText)
             );
     }
 }

Shipyard/ShipyardListImplement»/Implements/MessageInfoStorage.cs

@@ -72,5 +72,18 @@ namespace ShipyardListImplement_.Implements
             _source.Messages.Add(newMessage);
             return newMessage.GetViewModel;
         }
+
+        public MessageInfoViewModel? Update(MessageInfoBindingModel model)
+        {
+            foreach (var message in _source.Messages)
+            {
+                if (message.MessageId == model.MessageId)
+                {
+                    message.Update(model);
+                    return message.GetViewModel;
+                }
+            }
+            return null;
+        }
     }
 }

Shipyard/ShipyardListImplement»/Models/Message.cs

@@ -41,7 +41,15 @@ namespace ShipyardListImplement_.Models
                 MessageId = model.MessageId
             };
         }
-
+        public void Update(MessageInfoBindingModel? model)
+        {
+            if (model == null)
+            {
+                return;
+            }
+            IsRead = model.IsRead;
+            AnswerText = model.AnswerText;
+        }
         public MessageInfoViewModel GetViewModel => new()
         {
             Body = Body,
@@ -49,7 +57,9 @@ namespace ShipyardListImplement_.Models
             DateDelivery = DateDelivery,
             SenderName = SenderName,
             ClientId = ClientId,
-            MessageId = MessageId
+            MessageId = MessageId,
+            AnswerText = AnswerText,
+            IsRead = IsRead
         };
     }
 }