InvalidCastException trying to return result of scalar function in OA

[Lisa]

I added a stored procedure to my OA data model and generated a domain method for it. The stored procedure returns an Integer result.
Here is the auto generated code:
​

Public FunctionSpGetCurrentWeight(ByVal fillStation As System.Nullable(Of System.Char)) As Int64 Implements IWWModelUnitOfWork.SpGetCurrentWeight
       Dim returnValue As Integer
       Return SpGetCurrentWeight(fillStation, returnValue)
End Function

Public Function SpGetCurrentWeight(ByVal fillStation As System.Nullable(Of System.Char), ByRef returnValue As Integer) As Int64 Implements IWWModelUnitOfWork.SpGetCurrentWeight
              Dim parameterReturnValue AsNew OAParameter()
              parameterReturnValue.Direction= ParameterDirection.ReturnValue
              parameterReturnValue.ParameterName= "parameterReturnValue"

              Dim parameterFillStation As New Telerik.OpenAccess.Data.Common.OAParameter
              parameterFillStation.ParameterName = "FillStation"
              If fillStation.HasValue Then
                     parameterFillStation.Value= fillStation.Value
              Else
                     parameterFillStation.DbType= DbType.String
                     parameterFillStation.Value= DBNull.Value
              End If
              Dim queryResult As Int64= Me.ExecuteScalar(Of Int64)("[dbo].[spGetCurrentWeight]", CommandType.StoredProcedure, parameterFillStation,
parameterReturnValue)

              If parameterReturnValue.Value Is DBNull.Value Then
                     returnValue= -1
              Else
                     returnValue= DirectCast(parameterReturnValue.Value, Integer)
              End If      

              Return queryResult
       End Function

I created the following function to get the result:

Imports WonderWareDataModel
Module WWDataLookups

    Public Function GetWeightFromWonderware(strBay As String) As Int64
        Dim lngWeight As Int64 = -999
        Try
            Using model As New WonderWareDataModel.WWModel               
                   lngWeight = model.SpGetCurrentWeight(strBay)
            End Using
        Catch
        End Try
        Return lngWeiight
    End Function
End Module

WHenever I call my function  GetWeightFromWonderware in my asp page codebehind, an error is thrown in the generated code SpGetCurrentWeight. It is an InvalidCastException at the line Dim queryResult As Int64=Me.ExecuteScalar(Of Int64)("[dbo].[spGetCurrentWeight]",CommandType.StoredProcedure, parameterFillStation, parameterReturnValue).

Can anyone spot what the error is. The sp does return an integer value for the "strBay" parameter that I am testing with.

Any help would be greatly appreciated. 

[Lisa]

Still struggling with this...Manually modified the generated function to return an object instead of an int and was able to see that the sp was returning a value of 0.  Modified again to return a double and it still worked. Does not work as an int though even though the tooltip over the returned value say " 0 (int)".
I can live with assigning it as a double instead of an integer even though I don't understand why. However the returned value should be 3264, not 0.  I thought perhaps it was returning the error code so I modified the sp to also set an output parameter and then regenerated my model function to pick that up instead. It still gets 0 as the return parameter and 0 as the output parameter. I know for a fact, the sp is not returning zero.
So why can't I get the correct value back? What am I doing wrong? Or is there a bug in open access?

[Kaloyan Nikolov]

Hello Lisa,

The value returned by the generated domain method is meant to return the number of affected records. In your case I would suppose you need to map the stored procedure with ResultType: None (see the attached image). 

You can access your return value with a overload of the domain method with an out parameter named returnValue, like the code below:

Using context = New EntitiesModel1()
    Dim returnCode As Integer

    context.GetMeAnInteger(returnCode)
End Using

You can see the above store procedure mapping in the attached sample project.

I hope this helps. Should you have any further questions do not hesitate to get back to us. 


Regards,
Kaloyan Nikolov
Telerik