<%@ WebService language="VB" class="autenticazione" %>

Imports System
Imports System.Web.Services
Imports System.Xml.Serialization


Public Class autenticazione

    Function Database(ByVal usr As String, ByVal psw As String) As Boolean
        Dim connectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0; Ole DB Services=-4; Data Source=D:\Web\Tiw\messenger\messenger.mdb"
        Dim dbConnection As System.Data.IDbConnection = New System.Data.OleDb.OleDbConnection(connectionString)

        Dim queryString As String = "SELECT [utenti].[psw], [utenti].[usr], [utenti].[nickname] FROM [utenti] WHERE (("& _
        "[utenti].[usr] = @usr) AND ([utenti].[psw] = @psw))"
        Dim dbCommand As System.Data.IDbCommand = New System.Data.OleDb.OleDbCommand
        dbCommand.CommandText = queryString
        dbCommand.Connection = dbConnection

        Dim dbParam_usr As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_usr.ParameterName = "@usr"
        dbParam_usr.Value = usr
        dbParam_usr.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_usr)
        Dim dbParam_psw As System.Data.IDataParameter = New System.Data.OleDb.OleDbParameter
        dbParam_psw.ParameterName = "@psw"
        dbParam_psw.Value = psw
        dbParam_psw.DbType = System.Data.DbType.String
        dbCommand.Parameters.Add(dbParam_psw)

        dbConnection.Open()

        if dbConnection.usr = usr and dbConnection.psw = psw then
            Return True
        Else
            Return False
        End If

    End Function


    <WebMethod> Public Function Autenticazione(usr As String, psw As String) As Boolean
        Return Database(usr, psw)
    End Function

End Class

if dbConnection.usr = usr and dbConnection.psw = psw then 
Return True 
Else 
Return False 
End If