1

我正在编写一个应用程序，允许我们的用户向他们的联系人发送新闻通讯。这是数据库结构（仅重要字段）：

Contacts(tbl)       ContactEmails(tbl)       Newsletters(tbl)
  ContactID           ContactEmailID           NewsletterID
  ...                 ContactID (fk)           ...
                      EmailAddress             
                      Deleted
                      ...


NewsletterLists(tbl)       NewsletterToLists(tbl)
  NewsletterListID           NewsletterID (fk)
  ...                        NewsletterListID (fk)


NewsletterListToContacts(tbl)
  NewsletterListID (fk)
  ContactID (fk)
  Active
  Deleted
  UnsubscribedOn
  ...

现在我有一个结构为：

public class NewsletterContactEmails
{
    public int ContactID { get; set; }
    public List<string> EmailList { get; set; }
}

我想为每个联系人创建一个 NewsletterContactEmails 对象，这样我就可以遍历它并为每个联系人（而不是每个电子邮件地址）发送一封电子邮件。

我有 Newsletter 对象可以开始使用。所以在伪它将是......

1. Get NewsletterLists this newsletter is to send to.
2. Get Active (double opted-in) and non-deleted/unsubscribed DISTINCT Contact List from said NewsletterLists.
3. Create NewsletterContactEmails object for each contact and add their non-deleted DISTINCT list of email addresses.

我想在一个查询中做到这一点。这是我目前拥有的，我想我已经接近了，但这甚至不会编译：

List<NewsletterContactEmails> Recipients = objNewsletter.NewsletterToLists
                    .Select(ntl => ntl.NewsletterList.NewsletterListToContacts
                        .Where(nl => nl.Active == true && nl.Deleted == false && nl.UnsubscribedOn == null)
                        .Select(nl => new NewsletterContactEmails {
                            ContactID = nl.ContactID,
                            EmailList = nl.Contact.ContactEmails.Where(ce => ce.Deleted == false).Select(ce => ce.EmailAddress).Distinct().ToList()
                        }));

任何帮助是极大的赞赏！

4

1 回答 1

3 
List<NewsletterContactEmails> Recipients = objNewsletter.NewsletterToLists
    .SelectMany(ntl => ntl.NewsletterList.NewsletterListToContacts
        .Where(nl => nl.Active == true && nl.Deleted == false && nl.UnsubscribedOn == null)
        .Select(nl => new NewsletterContactEmails
        {
            ContactID = nl.ContactID,
            EmailList =
                nl.Contact.ContactEmails.Where(ce => ce.Deleted == false)
                    .Select(ce => ce.EmailAddress)
                    .Distinct()
                    .ToList()
        }));

尝试第一个选择 asSelectMany而不是Select

于 2013-09-24T03:06:07.057 回答