相关疑难解决方法(0)

我正在使用MVC 4,我必须使用Code First Migrations更新我的数据库.我要做的是从数据库表中选择记录,并将它们插入下拉列表,用户可以在其中选择一个.

我有一个我不明白的错误:

LINQ to Entities does not recognize the method 'System.String ToString()' method, and this method cannot be translated into a store expression.

控制器:

  public ActionResult Addnew()
        {
            var dba = new DefaultConnection();
            var query = dba.blob.Select(c => new SelectListItem
            {
                Value = c.id.ToString(),
                Text = c.name_company,
                Selected = c.id.Equals(3)
            });
            var model = new Companylist
            {
                xpto = query.AsEnumerable()
            };

            return View(model);
        }

我有以下查询:

from a in Products
select new ProductVM
    {
         id = a.id,
         modified = a.modified.ToString()
    }

这给了我一个错误:

LINQ to Entities does not recognize the method 'System.String ToString()'
method, and this method cannot be translated into a store expression.

该modified产品表的日期时间.将modified在ProductVM类是字符串.

有任何想法吗？这必须是一个微不足道的问题.