Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click
        db.ConnectionString = "Data Source=Zeus-vaio;Initial Catalog=liceo;Integrated Security=SSPI;"
        db.Open()
        REM controlli campi blank
        If Me.TextBox4.Text = String.Empty Then
            Page.RegisterStartupScript("ScriptDescription", "<script type=""text/javascript"">alert('Campo docente: vuoto');</script>")
            Return
        ElseIf Me.TextBox1.Text = String.Empty Then
            Page.RegisterStartupScript("ScriptDescription", "<script type=""text/javascript"">alert('Campo nome utente: vuoto');</script>")
            Return
        ElseIf Me.TextBox2.Text = String.Empty Then
            Page.RegisterStartupScript("ScriptDescription", "<script type=""text/javascript"">alert('Campo password: vuoto');</script>")
            Return
        ElseIf Me.TextBox3.Text = String.Empty Then
            Page.RegisterStartupScript("ScriptDescription", "<script type=""text/javascript"">alert('Campo indirizzo email: vuoto');</script>")
            Return
        End If
        REM----------------------
        REM recupero il nome utente per controllo
        Dim Nome_Utente As String = String.Empty
        Try
            sqlcmd.CommandText = "Get_nomeutente"
            sqlcmd.Parameters.Add("@nomeutente", SqlDbType.VarChar).Value = Me.TextBox1.Text
            sqlcmd.Connection = db
            sqlcmd.CommandType = CommandType.StoredProcedure
            sqldr = sqlcmd.ExecuteReader
            If sqldr.Read() Then
                Nome_Utente = sqldr.GetSqlString(0).Value
            End If
            sqldr.Close()
            sqlcmd.Parameters.Clear()
            sqlcmd.Dispose()
        Catch ex As Exception
            Page.RegisterStartupScript("ScriptDescription", "<script type=""text/javascript"">alert('" & ex.Message & "');</script>")
            Return
        End Try
        If Nome_Utente = Me.TextBox1.Text Then
            Page.RegisterStartupScript("ScriptDescription", "<script type=""text/javascript"">alert('Nome utente già utilizzato!');</script>")
            Return
        End If
        REM--------------------------------------
        Try
            sqltrans = db.BeginTransaction
            sqlcmd.Transaction = sqltrans
            sqlcmd.CommandText = "InsUtenti"
            sqlcmd.Parameters.Add("@Docente", SqlDbType.VarChar).Value = Me.TextBox4.Text
            sqlcmd.Parameters.Add("@nomeutente", SqlDbType.VarChar).Value = Me.TextBox1.Text
            sqlcmd.Parameters.Add("@password", SqlDbType.VarChar).Value = Me.TextBox2.Text
            sqlcmd.Parameters.Add("@email", SqlDbType.VarChar).Value = Me.TextBox3.Text
            sqlcmd.Connection = db
            sqlcmd.CommandType = CommandType.StoredProcedure
            sqlcmd.ExecuteNonQuery()
            sqltrans.Commit()
            sqlcmd.Parameters.Clear()
            sqlcmd.Dispose()
            Response.Redirect("conferma.aspx")
        Catch ex As Exception
            sqltrans.Rollback()
            Page.RegisterStartupScript("ScriptDescription", "<script type=""text/javascript"">alert('" & ex.Message & "');</script>")
            Return
        End Try
        db.Close()
        db.Dispose()
    End Sub