LINQ to Entities无法识别方法'System.DateTime ConvertShamsiToMiladi（System.String）'方法

Question

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

How do I fix it?

my codes :

var _48hoursAgoDate = DateTime.Now.AddDays(-2);
var _48hoursAgoPayments =_paymentService.GetMany(d => d.Date.ConvertShamsiToMiladi() >= _48hoursAgoDate)

extension method :

public static DateTime ConvertShamsiToMiladi(this string source)
{
    var date = source.Split('/');
    return new DateTime(int.Parse(date[0]), int.Parse(date[1]), int.Parse(date[2]), new PersianCalendar());
}

Answer 1

You have this message because Linq doesent know how to translate your method to SQL You should convert it to Linq to object first by using .AsEnumerable() it should look like this :

var _48hoursAgoPayments =_paymentService.AsEnumerable().GetMany(d => d.Date.ConvertShamsiToMiladi() >= _48hoursAgoDate)

Regards,

Answer 2

Using LINQ to Entities your query is converted to SQL and ConvertShamsiToMiladi is not implemented in SQL. You either select with a proper statement and convert the date afterwards, or do the whole selection on the client side, ie with _paymentService.AsEnumerable().GetMany(...) .

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