c# - 作为可投影对象的类和结构

Question

很多时候我必须从一个类中选择所需的字段，就像在 sql 中从表中选择所需的字段一样。所以我正在考虑将我的类和结构作为 Projectables。

这是我想要实现的。

public class Email
{
    public string Subject { get; set; }
    public string To { get; set; }
    public string Cc { get; set; }
    public string Bcc { get; set; }
    public string Body { get; set; }
    public DateTime ReceivedDate { get; set; }
}

public class EmailProjection
{
   // instead of this 

    //public string Subject { get; set; }
    //public DateTime ReceivedDate { get; set; }

    // I want to do this
    Email.Project(Subject,ReceivedDate);
}

public class EntryPoint
{
    static void Main()
    {
        var emailList = new List<Email>();
        /* populate  emails here from source*/

        // I want to do this
        List<EmailProjection> emailProjectionList = emailList.Project(EmailProjection).ToList();

        // rather than 
        List<EmailProjection> emailProjectionList= emailList.Select(email=>new {email.Subject,email.ReceivedDate}).ToList();}
    }

有人可以帮我解决这个问题吗？提示??它可以实现吗？

Answer 1

你可以看看Automapper:https://github.com/AutoMapper/AutoMapper .它是一个基于命名约定和规则映射 DTO 的库。看看维基有一个 Projection页，那可能就是您要找的那个。只是为了连接您的示例，您最终可以编写如下代码:

Mapper.Map<EMail, EmailProjection>(yourObjects);