New Post: Fetch all messages from inbox

hi pavel, i want to fetch all messages from inbox without any specific search, i'm sahring what i have done so far please guide me please.

public async Task getMessage()

    {

        using (var client = new ImapClient("imap.gmail.com", true))
        {

            // Download only the headers we need
            client.Behavior.RequestedHeaders = new[] 
            {
                MessageHeader.ContentType,
                MessageHeader.Date,
                MessageHeader.From,           
                MessageHeader.MessageId
            };

            // Do not examine folders, it will gain us performance
            client.Behavior.ExamineFolders = false;

            // Download body, attachments, flags and headers
            client.Behavior.MessageFetchMode = MessageFetchMode.Body | MessageFetchMode.Attachments | MessageFetchMode.Flags | MessageFetchMode.Headers;

            // Connecting
            if (client.Connect())
            {
                // Sign in
                if (client.Login("abcd@gmail.com", "abcdef"))
                {

                    var excludeLabels = new string[] { "Processed", "Research", "MANUAL", "Failed", "Success", "Duplicate" };


                    // Building the search query
                    var query = string.Format("X-GM-RAW \"{0} -({1})\"",
                                                    string.Join(" OR ", "ALL"),
                                                    string.Join(" OR ", excludeLabels.Select(label => "(label:" + label + ")")));

                    var messages = client.Folders.Inbox.Search(query, MessageFetchMode.ClientDefault, 1000);

                    foreach (var msg in messages)
                    {
                        // Mark the message as seen
                        msg.Seen = true;
                        string plainTextBody = msg.Body.HasText ? msg.Body.Text : "";
                        string htmlBody = msg.Body.HasHtml ? msg.Body.Html : "";

                        var time = DateTime.SpecifyKind(msg.Date.HasValue ? msg.Date.Value : DateTime.Now, DateTimeKind.Utc);

                        if (msg.Attachments.Count() > 0)
                        {
                            foreach (var file in msg.Attachments)
                            {
                                var folder = Server.MapPath("~/Data/InboxAttachments");
                                if (!Directory.Exists(folder))
                                {
                                    Directory.CreateDirectory(folder);
                                }
                                string guid = Guid.NewGuid().ToString();
                                string webPath = null;
                                msg.Download(MessageFetchMode.Full);
                                int posOfDot = file.FileName.LastIndexOf(".");
                                string fName = Guid.NewGuid().ToString() + file.FileName.Substring(posOfDot);
                                webPath = "~/Data/InboxAttachments/" + fName;
                                file.Save(Server.MapPath("~/Data/InboxAttachments"), fName);

                                db.MailSystems.AddOrUpdate(c => c.MESSAGEID, new MailSystem
                                {
                                    Message = htmlBody,
                                    Date = time,
                                    Attachment = webPath,
                                    EmailType = "IMAP",
                                    Subject = string.IsNullOrEmpty(msg.Subject) ? "No Subject" : msg.Subject,
                                    Sender = msg.Sender.Address,
                                    MESSAGEID = msg.MessageId
                                });
                            }
                        }
                        else
                        {                                
                            db.MailSystems.AddOrUpdate(c => c.MESSAGEID, new MailSystem
                            {
                                Message = htmlBody,
                                Date = time,
                                //   Attachment = webPath,
                                EmailType = "IMAP",
                                Subject = string.IsNullOrEmpty(msg.Subject) ? "No Subject" : msg.Subject,
                                Sender = msg.Sender.Address,
                                MESSAGEID = msg.MessageId
                            });
                        }

                        await db.SaveChangesAsync();                            
                    }
                }
            }
        }
    }

i'm getting error on this line "db.MailSystems.AddOrUpdate(c => c.MESSAGEID, new MailSystem"
error is "object reference not set to an instance of an object", i think it is not downloading messages becasue when i insert certain email query it will fetch the messages normally but i want all my inbox messages, please guide me