Question

I am calling a SQL proc that has 3 OUTPUT params. After the call to the proc one of the params does not return a value when the other two do. Profiler shows that all 3 values are being returned.

The params are declared as follows in the proc…

@UsrVariableID INT OUTPUT, @OrganisationName NVARCHAR(256) OUTPUT, @Visible bit OUTPUT 

and the code that calls the proc is like this…

cm.Parameters.AddWithValue('@OrganisationName', name); cm.Parameters['@OrganisationName'].Direction = ParameterDirection.Output; cm.Parameters.AddWithValue('@Visible', visible); cm.Parameters['@Visible'].Direction = ParameterDirection.Output;  cm.ExecuteNonQuery();  name = cm.Parameters['@OrganisationName'].Value.ToString(); visible = bool.Parse(cm.Parameters['@Visible'].Value.ToString()); id = int.Parse(cm.Parameters['@UsrVariableID'].Value.ToString()); 

The param that fails is @OrganisationName.

I’m wondering if its because the param is of type string in the code but NVARCHAR in the proc.

Anyone got any ideas?

Answer 1

With output parameters that have variable length data types (nvarchar, varchar, etc), I’ve found that being more explicit leads to better results. In the case you’ve posted, a type is not specified on the C# side. I would probably change things to look something like the following:

SqlParameter theOrganizationNameParam = new SqlParameter( '@OrganisationName', SqlDbType.NVarChar, 256 ); theOrganizationNameParam.Direction = ParameterDirection.Output; cm.Parameters.Add( theOrganizationNameParam ); cm.ExecuteNonQuery(); name = theOrganizationNameParam.Value; 

With this you can guarantee the output paratmer has the correct data type, and therefore can access the Value property without and exception being thrown.

Hope this sheds some light.