C# Linq 如果日期以字符串格式存储在数据库中，则 2 个日期之间的日期

Question

I want to get data using c# linq between two dates but the date stored in the database is in string format.

DateTime dFrom = DateTime.ParseExact("01-04-2019", "dd-MM-yyyy", CultureInfo.InvariantCulture);

DateTime dTo = DateTime.ParseExact("02-04-2019", "dd-MM-yyyy", CultureInfo.InvariantCulture);  

 var List = (from Receipt in DB.tbl_PurchaseReceipts 
             where DateTime.ParseExact(Receipt.Date, "dd-MM-yyyy", CultureInfo.InvariantCulture) >= dFrom && DateTime.ParseExact(Receipt.Date, "dd-MM-yyyy", CultureInfo.InvariantCulture) <= dTo
             select Receipt).ToList();

Getting Error:

Method 'System.DateTime ParseExact(System.String, System.String, System.IFormatProvider)' has no supported translation to SQL.

Answer 1

You should be able to parse out the parts manually and build a new DateTime :

var List = (from Receipt in DB.tbl_PurchaseReceipts 
            let rDate = new DateTime(Convert.ToInt32(Receipt.Date.Substring(6,4)),Convert.ToInt32(Receipt.Date.Substring(0,2)),Convert.ToInt32(Receipt.Date.Substring(3,2)))
            where dFrom <= rDate && rDate <= dTo
            select Receipt)
           .ToList();