我的程序里有这么一段代码：
order.OrderExpressInfo = (from oei in orderExpressRepository.Entities
where oei.OrderId == order.OrderId
select new EbcBuy.Bll.Orders.Models.OrderExpress
{
ContentInfo = oei.ContentInfo,
CreatedTime = oei.CreatedTime,
CreatedUserId = oei.CreatedUserId,
ExpressId = oei.ExpressId,
ExpressName = oei.ExpressName,
ExpressOrderId = oei.ExpressOrderId,
Freight = oei.Freight,
Manifest = oei.Manifest,
OrderId = oei.OrderId,
ReceiverContactInfo = new ContactInfoModel()
{
ZipCode = oei.CustomerZipCode,
Telephone = oei.CustomerPhone,
MobilePhone = oei.CustomerTel,
Address = oei.CustomerAddress,
LinkMan = oei.CustomerReceiverName,
ProvinceId = oei.CustomerArea.ProvinceId,
ProvinceName = oei.CustomerArea.ProvinceName,
CityId = oei.CustomerArea.CityId,
CityName = oei.CustomerArea.CityName,
CountyId = oei.CustomerArea.DistrictId,
CountyName = oei.CustomerArea.DistrictName
},
ShopId = order.OrderId,
ShopName = order.ShopName,
ShopContactInfo = new ContactInfoModel()
{
ZipCode = oei.ShopZipCode,
Telephone = oei.ShopTel,
MobilePhone = oei.ShopPhone,
Address = oei.ShopAddress,
LinkMan = oei.ShopLinkMan,
ProvinceId = oei.ShopArea.ProvinceId,
ProvinceName = oei.ShopArea.ProvinceName,
CityId = oei.ShopArea.CityId,
CityName = oei.ShopArea.CityName,
CountyId = oei.ShopArea.DistrictId,
CountyName = oei.ShopArea.DistrictName
}
}).FirstOrDefault();
其中，ContactInfoModel是一个实体类，定义了买家或卖家的contact信息， 实体类 EbcBuy.Bll.Orders.Models.OrderExpress
具备两个该类型的属性， ReceiverContactInfo和ShopContactInfo。 这里使用linq to entity要给这2个属性赋值， 要注意了，这里给ContactInfoModel初始化设置的属性个数和顺序必须相同。 否则，运行时会报如下异常：
“System.NotSupportedException”类型的未经处理的异常在 EntityFramework.dll 中发生
其他信息: 在单个 LINQ to Entities 查询中的两个结构上不兼容的初始化过程中出现类型“EbcBuy.Bll.Common.Models.ContactInfoModel”。类型可以在同一查询中的两个位置初始化，但前提是在这两个位置设置了相同的属性，且这些属性是以相同的顺序设置的。
我这个ContactInfoModel在项目里好多的linq to entity代码里进行这样的初始化， 为了提高复用，我把上面的初始化封装成了一个方法， 供各处调用。 修改后的代码如下：
order.OrderExpressInfo = (from oei in orderExpressRepository.Entities
where oei.OrderId == order.OrderId
select new EbcBuy.Bll.Orders.Models.OrderExpress
{
ContentInfo = oei.ContentInfo,
CreatedTime = oei.CreatedTime,
CreatedUserId = oei.CreatedUserId,
ExpressId = oei.ExpressId,
ExpressName = oei.ExpressName,
ExpressOrderId = oei.ExpressOrderId,
Freight = oei.Freight,
Manifest = oei.Manifest,
OrderId = oei.OrderId,
ReceiverContactInfo = GetCustomerContactInfoModelFromPO(oei),
ShopId = order.OrderId,
ShopName = order.ShopName,
ShopContactInfo = GetShopContactInfoModelFromPO(oei)
}).FirstOrDefault();
GetCustomerContactInfoModelFromPO和GetShopContactInfoModelFromPO定义很简单，你懂的。结果，在运行时，文章标题提到的异常出现了：“System.NotSupportedException”类型的未经处理的异常在 EntityFramework.dll 中发生 其他信息: LINQ to Entities 不识别方法“EbcBuy.Bll.Common.Models.ContactInfoModel GetCustomerContactInfoModelFromPO(EbcBuy.Dal.Orders.Models.OrderInfo)”，因此该方法无法转换为存储表达式。
【园子里搜索了一下， 有如下结论】在LINQ to Entities 中,使用lambada或linq时,变量一定要提前转换好,可不能到lambada里或linq里再转换。如:
var o= _db.Dictionary.Where(x => x.Type.Equals(type4.ToString()));
.ToString必然产生错误,应该:
string t=type4.ToString();
var o= _db.Dictionary.Where(x => x.Type.Equals(t));
用lambada或linq时,不要尝试去转换内置类型,是不允许的,如:
string t=type4.ToString();
var o= _db.Dictionary.Where(x => Convert.ToString(x.Type).Equals(t));
Convert.ToString必然要出错.
可以考虑使用如下方式：
using System.Data.Objects.SqlClient; //在 System.Data.Entity.dll 中
//获取市级地区
public JsonResult GetCity(string id)
{
var city = from c in db.AreaDivide
where SqlFunctions.StringConvert((double)c.ParentID) == id
select new { text = c.AreaName, value = c.ID };
return Json(city.ToList(), JsonRequestBehavior.AllowGet);
}
不过，像我这种情况，无法复用的话，还真是谈不上简洁性了。不晓得还有没有什么好的解决办法...
LINQ to Entities不识别方法***，因此该方法无法转换为存储表达式