Can't get a string from SQL query

[Andrew Morton]

I've got a stored procedure which works as expected using Run Stored
Procedure in VS.NET:-
-----------------------------------------------------------
ALTER PROCEDURE dbo.ValidateUse r
@Username nVarChar(50),
@Password nVarChar(24),
@Valid nvarchar(36) OUTPUT
as
Select @Valid=cast(Use rID as nvarchar(36)) From userdata
Where Username=@Usern ame
and Password=@Passw ord
-----------------------------------------------------------

UserID is a uniqueIdentifie r.

But I can't get a value from @Valid in VB.NET using an output paramater,
it's always an empty string:-
-----------------------------------------------------------
Private sqlConnectionSt ring As String =
ConfigurationSe ttings.AppSetti ngs("sqlConnect ionString")

Public Function validateUser(By Val nam As String, ByVal pwd As String) As
String
Dim sqlCmd As New SqlCommand("val idateUser", sqlConn)
sqlCmd.CommandT ype = CommandType.Sto redProcedure

Dim sqlParam As New SqlParameter("@ UserName", SqlDbType.NVarC har)
sqlParam.Value = Trim(nam)
sqlCmd.Paramete rs.Add(sqlParam )

sqlParam = New SqlParameter("@ Password", SqlDbType.NVarC har)
sqlParam.Value = Trim(pwd)
sqlCmd.Paramete rs.Add(sqlParam )

Dim sqlParamUserID As New SqlParameter("@ Valid", SqlDbType.NVarC har)
sqlParamUserID. Value = ""
sqlParamUserID. Direction = ParameterDirect ion.Output
sqlCmd.Paramete rs.Add(sqlParam UserID)

Try
If sqlConn.State <> ConnectionState .Open Then
sqlConn.Open()
End If
sqlCmd.ExecuteR eader()
Catch e As Exception
Throw e
End Try

sqlConn.Close()

Return CType(sqlParamU serID.Value, String)
End Function
-----------------------------------------------------------

However, if I change the stored procedure to return an int (e.g. select
@Valid=count(*) ), and change the VB to expect a number then it does work.

What am I doing wrong?

Andrew

[Andrew Morton]

Andrew Morton wrote:

ALTER PROCEDURE dbo.ValidateUse r
@Username nVarChar(50),
<snip>
Dim sqlParam As New SqlParameter("@ UserName", SqlDbType.NVarC har)

Solution: use the size parameter, as in
Dim sqlParam As New SqlParameter("@ UserName", SqlDbType.NVarC har, 50)

Andrew