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[英]Entity Framework Core 3.1 Enum Conversion failed when converting the nvarchar value 'EnumValue' to data type int
[英]C# Entity Framework Error Converting nvarchar to int by enum
我遇到以下错误:
Conversion failed when converting the nvarchar value 'HolidayRequest' to data type int.
我在实体框架中有一个继承结构。 我的基本模型如下:
public abstract class Request
{
public int ID { get; set; }
public int EmployeeID { get; set; }
public string Subject { get; set; }
[Display(Name = "Date Requested")]
public DateTime DateRequested { get; set; }
[Display(Name = "Start Date")]
public DateTime StartDateTime { get; set; }
[Display(Name = "Return To Work Date")]
public DateTime EndDateTime { get; set; }
public RequestStatus Status { get; set; }
public string Notes { get; set; }
public int? ResponseID { get; set; }
public RequestDiscriminator Discriminator { get; set; }
[ForeignKey("EmployeeID")]
public virtual Employee Employee { get; set; }
[ForeignKey("ResponseID")]
public virtual Response Response { get; set; }
}
当我尝试从数据库中检索数据时,如下所示:
public IQueryable<Request> GetPendingHolidayRequestsByEmployeeId(int employeeId)
{
var list = _context.Requests.Where(p => p.Discriminator == RequestDiscriminator.Holiday && p.EmployeeID == employeeId && p.Status == RequestStatus.NotProcessed);
return list;
}
这是发生错误的地方。
考虑到错误的上下文,我认为此枚举public RequestDiscriminator Discriminator { get; set; }
public RequestDiscriminator Discriminator { get; set; }
枚举的结构为:
public enum RequestDiscriminator
{
Holiday,
Absence
}
实体框架发送的SQL语句为:
SELECT
[Extent1].[ID] AS [ID],
CASE WHEN ([Extent1].[Discriminator1] = N'AbsenceRequest') THEN '0X0X' ELSE '0X1X' END AS [C1],
[Extent1].[EmployeeID] AS [EmployeeID],
[Extent1].[Subject] AS [Subject],
[Extent1].[DateRequested] AS [DateRequested],
[Extent1].[StartDateTime] AS [StartDateTime],
[Extent1].[EndDateTime] AS [EndDateTime],
[Extent1].[Status] AS [Status],
[Extent1].[Notes] AS [Notes],
[Extent1].[ResponseID] AS [ResponseID],
[Extent1].[Discriminator] AS [Discriminator]
CASE WHEN ([Extent1].[Discriminator1] = N'AbsenceRequest') THEN [Extent1].[ReasonCode] END AS [C2],
CASE WHEN ([Extent1].[Discriminator1] = N'AbsenceRequest') THEN [Extent1].[TakenPaid] END AS [C3],
CASE WHEN ([Extent1].[Discriminator1] = N'AbsenceRequest') THEN CAST(NULL AS float) ELSE [Extent1].[TotalDays] END AS [C4],
CASE WHEN ([Extent1].[Discriminator1] = N'AbsenceRequest') THEN [Extent1].[Employee_EmployeeID] END AS [C5],
CASE WHEN ([Extent1].[Discriminator1] = N'AbsenceRequest') THEN CAST(NULL AS int) ELSE [Extent1].[Employee_EmployeeID1] END AS [C6]
FROM [dbo].[Request] AS [Extent1]
WHERE ([Extent1].[Discriminator1] IN (N'AbsenceRequest',N'HolidayRequest')) AND (0 = [Extent1].[Discriminator]) AND (0 = [Extent1].[Status])
任何帮助将不胜感激,因为我完全陷入了困境。
UPDATE
按照下面答案的建议,我从数据库中删除了两个Discriminator列,并读取了我的。 但是,SQL查询似乎仍在寻找Discriminator1列,该列现在不存在。
我设法解决了这个问题。 答案是删除我创建的discriminator列,并允许EF通过在linq查询中包括以下类型来确定类型:
var test = _context.Requests.Where(r => r.EmployeeID == employeeId).OfType<AbsenceRequest>();
OfType <>()似乎告诉EF查看该类型名称的Discriminator列,并且仅返回该类型的数据。
看起来您在“ Discriminator1”中有一个额外的列。 您最初是否将该字段作为字符串,然后尝试将其转换为枚举? 最好的选择是尝试完全删除该字段,并确保同时删除Discriminator和Discriminator1。 然后尝试重新添加。 当具有自定义映射时,可能会发生这种情况,因此可能会出现问题。
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