Question

我必须多次从类中选择必需的字段，就像在sql中从Table中选择所需字段一样。所以我想把我的类和结构化为Projectables。

这是我想要实现的目标。

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

您可以查看Automapper：https://github.com/AutoMapper/AutoMapper。它是一个基于命名约定和规则映射DTO的库。在维基中查看有一个Projection页面，可能是您正在寻找的页面。只是为了连接你的例子，你最终可以编写如下代码：

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

类和结构作为可投影仪

1 个答案: