Linq 如何在双向条件下获得根据查询/票证发现的新信息

我正在使用crm应用程序。我最终开发了它，我很困惑我是如何根据标志必须显示和消息不必须为真来检测新消息的

这是我的db模式，用于理解这个问题

以下是我构造的查询，用于获取新邮件计数：

int new_messages = 0;
                foreach (var enquiry in db.Enquiries.Where(i => (i.ForwardTo.Equals(userid) || i.AttendBy.Equals(userid))).ToList())
                {
                    if (enquiry != null)
                    {
                        bool IsIns = true;
                        foreach (var flag in db.Flags.Where(f => f.Enquiry_History_id.Equals(enquiry.Ref_no) && f.User_id.Equals(userid)).Select(f => new { IsDisplay = f.IsDisplay }).ToList())
                        {
                            if (flag != null)
                            {
                                if (flag.IsDisplay == false)
                                {
                                    IsIns = false;
                                }
                            }
                        }
                        if (IsIns == true)
                        {
                            foreach (var message in db.Messages.Where(m => m.Enquiry_History_id.Equals(enquiry.Ref_no) && m.User_id.Equals(userid)).Select(m => new { IsRead = m.IsRead }).ToList())
                            {
                                if (message.IsRead == true)
                                {
                                    //do another stuff
                                }
                                else
                                {
                                    new_messages++;
                                }
                            }
                        }
                    }
                }
                lbl_msg.Text = new_messages.ToString();

---

在这里，我必须采取的每一个查询已经注意到或转发给用户，并检查它首先应该是显示是不是假的，然后根据每个消息检查不应该有读为真。我正在尝试我最好的方法，但这并没有给我想要的结果。

我有一个想法，只需插入两个值，一个为true，生成消息，另一个为false，向前。并且只找出那些是假的

像这样：

using (DataClassesDataContext db = new DataClassesDataContext())
        {
            string userid = db.Users.Where(u => u.Username.Equals((String)Session["Username"])).Select(u => u.Ref_no).SingleOrDefault().ToString();
            bool IsIns = true;
            foreach (var enquiry in db.Enquiries.Where(i => i.AttendBy.Equals(userid) || i.ForwardTo.Equals(userid)).ToList())
            {
                if (enquiry != null)
                {
                    foreach (var flag in db.Flags.Where(f => f.Enquiry_History_id.Equals(enquiry.Ref_no) && f.User_id.Equals(userid)).Select(f => new { IsDisplay = f.IsDisplay }).ToList())
                    {
                        if (flag.IsDisplay == false)
                        {
                            IsIns = false;
                        }
                        if (IsIns == true)
                        {
                            foreach (var message in db.Messages.Where(m => m.Enquiry_History_id.Equals(enquiry.Ref_no)).ToList())
                            {
                                if (message != null)
                                {
                                    bool IsIns1 = false;
                                    foreach (var messageflag in db.MessageFlags.Where(mf => mf.MessageId.Equals(message.Id) && mf.UserId.Equals(userid)).Select(mf => new
                                    {
                                        IsRead = mf.IsRead,
                                        User_id = mf.UserId,
                                        Message = message.body,
                                        CreatedDate = message.Created_date
                                    }).ToList())
                                    {
                                        if (messageflag.IsRead == false)
                                        {
                                            IsIns1 = true;
                                        }
                                        if (IsIns1 == true)
                                        {
                                            DataRow dr = dt.NewRow();
                                            dr["Ref_no"] = enquiry.Ref_no.ToString();
                                            dr["Name"] = db.Users.Where(u => u.Ref_no.Equals(messageflag.User_id)).Select(u => u.FirstName + ' ' + u.LastName).SingleOrDefault().ToString();
                                            dr["UserId"] = db.Users.Where(u => u.Ref_no.Equals(messageflag.User_id)).Select(u => u.Ref_no).SingleOrDefault().ToString();
                                            dr["Message"] = messageflag.Message.ToString();
                                            dr["CreatedDate"] = messageflag.CreatedDate.ToString();
                                            dt.Rows.Add(dr);
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
            myDataSet.Tables.Add(dt);
            lbl_count_messages.Text = myDataSet.Tables[0].Rows.Count.ToString();
            if (myDataSet.Tables[0].Rows.Count == 0)
            {
                message_alert.Visible = false;
            }
            Repeater_Messages.DataSource = myDataSet;
            Repeater_Messages.DataBind();
        }