异常：指定的转换无效.v

Question

   at IBM.Data.DB2.Core.TypeMap.FromValue(Object oValue, Int32& iByteLength, DB2Connection connection, Int32 iArrayLength, String parameterName, Boolean bMultiRowCmd)
   at IBM.Data.DB2.Core.DB2Parameter.GetParamInfo(Int32 paramPos, DB2ParamInfo& paramInfo, Boolean chainBegin)
   at IBM.Data.DB2.Core.DB2ParameterCollection.GetParamInfoList(Boolean chainBegin)
   at IBM.Data.DB2.Core.DB2Command.ExecuteReaderObject(CommandBehavior behavior, String method, DB2CursorType reqCursorType, Boolean abortOnOptValueChg, Boolean skipDeleted, Boolean isResultSet, Int32 maxRows, Boolean skipInitialValidation)
   at IBM.Data.DB2.Core.DB2Command.ExecuteReaderObject(CommandBehavior behavior, String method)
   at IBM.Data.DB2.Core.DB2Command.ExecuteReader(CommandBehavior behavior)
   at IBM.Data.DB2.Core.DB2Command.ExecuteDbDataReader(CommandBehavior behavior)
   at System.Data.Common.DbCommand.ExecuteDbDataReaderAsync(CommandBehavior behavior, CancellationToken cancellationToken)
--- End of stack trace from previous location where exception was thrown ---

Exception was thrown at location where it has below lines of code. var dr = await cmd.ExecuteReaderAsync()

we have no issue with do.net core 2.1 but when we updated to do.net core 3.1 we are running into this issue.

update do.netcore 2.1 project used ibm.data.db2.core 1.3 do.netcore 3.1 project using ibm.data.db2.core 3.1(Unit test is passing though)

Answer 1

I got it working now. In dotnet core 2.1 the object value deserializes properly. In my case it is string where as in dotnet core 3.1 it is deserializes as JsonElement which was causing the issue and db2 was not recognizing the jsonelement as any type.

I switched my service to use Newtonsoftjson by adding services.AddControllers().AddNewtonsoftJson(); and now it is properly desearilizing it.

There is an open issue here for bool which is pretty much the same as my case but my object is of type string. They also suggest there to write a custom converter for Object.

Answer 2

In case someone stumbles upon this issue:

While one should configure desiralization properly, as pointed out by the accepted answer, in my case, I was trying to convert CHARACTER(1) SQL Type to char data type which is the same as Int32 .

The solution was to change the char data type to string . Inefficient but it does the job.