LINQ to Entities无法识别方法'System.String getFullname（System.String，System.String）'

Question

我试图从我的控制器操作方法中调用业务模型类的静态方法，但我失败了。 请我真的需要您的帮助。 谢谢

public ActionResult Index()
{

 var model =
                           _db.members
                           .Include(m =>m.homeTownCity)
                           .Include(m => m.currentCity)
                           .OrderBy(m => m.fname)
                           .ThenBy(m => m.lname)
                           .Select(m => new MembersListViewModel
                           {
                               homeTown = m.homeTownCity.Name,
                               currentCity = m.currentCity.Name,

                               //Calling a business class static method
                               Name= MemberManagement.getFullname(m.lname,m.fname),
                               spoken = m.spoken,
                               hasPosted = m.posts.Count()
                           });


           return View(model);
}

 public class MemberManagement
 {
        public static string getFullname( string fname,string lname) {

            string fullname = fname + "  " + lname;
            return fullname;
        }
}

Answer 1

这是因为您的静态方法不能转换为SQL并不能由实体框架执行。

首先将您的成员拉下来作为列表，然后进行选择，因为这将由服务器而不是在SQL级别执行。

var members =
                           _db.members
                           .Include(m =>m.homeTownCity)
                           .Include(m => m.currentCity)
                           .OrderBy(m => m.fname)
                           .ThenBy(m => m.lname).ToList();


var model = members.Select(m => new MembersListViewModel
                           {
                               homeTown = m.homeTownCity.Name,
                               currentCity = m.currentCity.Name,

                               //Calling a business class static method
                               Name= MemberManagement.getFullname(m.lname,m.fname),
                               spoken = m.spoken,
                               hasPosted = m.posts.Count()
                           }).ToList();