C# 查询错误：LINQ to Entities无法识别方法'；字符串ToString（）'；方法

我必须在编辑页面中选中复选框。为此，我有如下查询：

var queryFI=(from u in _db.User where u.UserID==id where u.IsActive==1
                             select u);
            var join_queryFI=from r in queryFI join f in _db.Financial on r.FinancialID equals f.FinancialID
                             into c
                             from d in c.DefaultIfEmpty()
                             select new viewpartial
                             {
                               Text = d.FiName,
                               Value = d.FinancialID.ToString(),
                               Selected = d.FinancialID == r.FinancialIntermediaryID ? true : false                              
                             };

            ViewBag.IfcList = join_queryFI.ToList();

我有一个错误：

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

请帮助

您可以使用方法而不是

ToString

---

请再试一次，

SqlFunctions.StringConvert（d.FinancialID）

执行查询后，您可以将其转换为字符串：

var queryFI = (from u in _db.User
                where u.UserID == id
                where u.IsActive == 1
                select u);
var join_queryFI = from r in queryFI
                    join f in _db.Financial on r.FinancialID equals f.FinancialID
                        into c
                    from d in c.DefaultIfEmpty()
                    select new viewpartial
                    {
                        Text = d.FiName,
                        Value = d.FinancialID,
                        Selected = d.FinancialID == r.FinancialIntermediaryID ? true : false
                    };

ViewBag.IfcList = join_queryFI.ToList().Select(x => new { Text = x.Text, Value = x.Value.ToString(), Selected = x.Selected }).ToList();

---

假设

d.FinancialID

可能是一个int，则必须强制转换为双精度或十进制（正如

SqlFunctions.StringConvert

没有重载将int作为参数）：因此

SqlFunctions.StringConvert（（double）d.FinancialID）