错误LINQ到实体无法识别方法'System.String的ToString()“方法,而这种方法不能被翻译成店前pression [英] Error LINQ to Entities does not recognize the method 'System.String ToString()' method, and this method cannot be translated into a store expression
问题描述
我跟MVC4,Entityframewor和工作的jqGrid,当我从读取数据库中的数据,我stucked本error.Many的你说的填充id字段来anothe变种,但IA没有得到确切的地方来写,我的在数据库ID字段是整数。所以请不要帮我。
u.Id是我从EF访问ID字段中,它显示出此错误。什么是另一种方法,并在那里把新的code。
我的控制器看起来像
I am working with MVC4 , Entityframewor and Jqgrid, when am fetching data from Database , i stucked with this error.Many of you said populate the id field to anothe var , but i a not getting where exactly to write it, and my Id field in Database is of Integer. so please do help me. u.Id is a Id field which i am accessing from EF, It showing this error. what is the alternate way, and where to put the new code. My Controller looks like
public JsonResult GetUserDetails(string sidx="Id", string sord="asc", int page=1, int rows=5)
{
int pageIndex = Convert.ToInt32(page) - 1;
int pageSize = rows;
int totalRecords = db.Users.Count();
int totalPages = (int)Math.Ceiling((float)totalRecords / (float)pageSize);
var userdata = db.Users.OrderBy(sidx + " " + sord).Skip(pageIndex * pageSize).Take(pageSize);
var jsonData = new
{
total = totalPages,
page,
records = totalRecords,
rows = (from u in userdata
select new
{
i = u.Id,
cell = new string[]{**u.Id.ToString()**, u.Name,u.Designation,u.City}
//cell = new string[] { "", "", "", "" }
}).ToArray()
};
return Json(jsonData);
}
我从过去每天的工作这一点,而不是从该得到缓解。
I am Working this from past a day, and not getting relief from this .
推荐答案
toString()方法不能转换为SQL查询。所以,你有几种选择:
Method ToString() cannot be translated to SQL query. So you have several options:
-
您可以从数据库中获得完整的用户数据实体,它在.NET code映射到字符串数组:
You can get full entity userdata from db and map it to string array in .net code:
var userdata = db.Users.OrderBy(sidx + " " + sord).Skip(pageIndex * pageSize).Take(pageSize).AsEnumerable();
var jsonData = new
{
total = totalPages,
page,
records = totalRecords,
rows = (
from u in userdata
select new
{
i = u.Id,
cell = new string[]{**u.Id.ToString()**, u.Name,u.Designation,u.City}
//cell = new string[] { "", "", "", "" }
}).ToArray()
};
2.You可以使用两个选择()
,首先从数据库获取数据,第二个它映射到字符串数组:
2.You can use two Select()
, first to get data from db, second to map it to your string array:
var userdata = db.Users.OrderBy(sidx + " " + sord).Skip(pageIndex * pageSize).Take(pageSize).Select(u=>new{u.Id, u.Name, u.Designation, u.City});
var jsonData = new
{
total = totalPages,
page,
records = totalRecords,
rows = (
from u in userdata.AsEnumerable()
select new
{
i = u.Id,
cell = new string[]{u.Id.ToString(), u.Name,u.Designation,u.City}
}).ToArray()
};
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