如何使用Dapper傳遞null參數

dapper

我有一個存儲過程,其參數沒有默認值,但可以為null。但我無法弄清楚如何使用Dapper傳遞null。我可以在ADO中做得很好。

connection.Execute("spLMS_UpdateLMSLCarrier", new { **RouteId = DBNull.Value**, CarrierId = carrierID, UserId = userID, TotalRouteRateCarrierId = totalRouteRateCarrierId },
                                        commandType: CommandType.StoredProcedure);

例外:

System.NotSupportedException was caught
  Message=The member RouteId of type System.DBNull cannot be used as a parameter value
  Source=Dapper
  StackTrace:
       at Dapper.SqlMapper.LookupDbType(Type type, String name) in C:\Dev\dapper-git\Dapper\SqlMapper.cs:line 348
       at Dapper.SqlMapper.CreateParamInfoGenerator(Identity identity) in C:\Dev\dapper-git\Dapper\SqlMapper.cs:line 1251
       at Dapper.SqlMapper.GetCacheInfo(Identity identity) in C:\Dev\dapper-git\Dapper\SqlMapper.cs:line 908
       at Dapper.SqlMapper.Execute(IDbConnection cnn, String sql, Object param, IDbTransaction transaction, Nullable`1 commandTimeout, Nullable`1 commandType) in C:\Dev\dapper-git\Dapper\SqlMapper.cs:line 532
       at Rating.Domain.Services.OrderRatingQueueService.UpdateLMSLCarrier(Int32 totalRouteRateCarrierId, Int32 carrierID, Int32 userID) in C:\DevProjects\Component\Main\Source\Rating\Source\Rating.Domain\Services\OrderRatingQueueService.cs:line 52
       at Benchmarking.Program.OrderRatingQueue() in C:\DevProjects\Component\Main\Source\Benchmarking\Source\Benchmarking\Program.cs:line 81
       at Benchmarking.Program.Main(String[] args) in C:\DevProjects\Component\Main\Source\Benchmarking\Source\Benchmarking\Program.cs:line 28
  InnerException: 

不能離開RouteId,給我一個錯誤,說明它是必需的。不能使用常規null或者給我另一個錯誤。無法更改存儲過程,它不屬於我。

一般承認的答案

我認為你應該能夠通過將null轉換為適當的類型來實現。我們假設RouteId是一個整數:

connection.Execute("spLMS_UpdateLMSLCarrier", new { RouteId = (int?)null, CarrierId = carrierID, UserId = userID, TotalRouteRateCarrierId = totalRouteRateCarrierId }, commandType: CommandType.StoredProcedure);

使用常規null時遇到的問題很可能是在沒有RouteId的情況下使用null時,編譯器無法推斷匿名類型中的RouteId類型。



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許可下: CC-BY-SA with attribution
不隸屬於 Stack Overflow
這個KB合法嗎? 是的,了解原因