Identical Database Entry Already?

Here's some code that says it should identify if a user already exists in my database. I have changed the code to match my database, but it seems to have somewhat the opposite affect, rejecting all names (even new ones) or accepting all names (including existing ones). The switch in situations occurs in the "if" statement towardsd the end, when I change the sign of objDR.RecordsAffected.  Do you have any idea what could be wrong? Thanks.

Function DoesUserExist(ByVal userName As String) As Boolean

Dim connectionString As String = "server='(local)Netsdk'; trusted_connection=true; Database='AuthorizedUsers'"

Dim sqlConnection As System.Data.SqlClient.SqlConnection = New System.Data.SqlClient.SqlConnection(connectionString)



Dim queryString As String = "SELECT [Users].[UserName] FROM [Users] WHERE ([Users].[UserName] = @UserName)"

Dim sqlCommand As System.Data.SqlClient.SqlCommand = New System.Data.SqlClient.SqlCommand(queryString, sqlConnection)

Dim Cmd as New SQLCommand(queryString, sqlConnection)

With Cmd.Parameters

.Add(New SQLParameter("@username", username))

End With



sqlConnection.Open

Dim blHasRows As Boolean

Dim objDR As System.Data.SqlClient.SqlDataReader = Cmd.ExecuteReader(system.data.CommandBehavior.CloseConnection)



if objDR.RecordsAffected > 0 then

blHasRows="True"

else

blHasRows="False"

End If



Return blHasRows



End Function