[كود] رسالة خطا اول مرة اقراها (native)

كود :

If al.Text.Trim.Replace(" ", "") = "" Then Exit Sub

        Dim thnote As New Thread(AddressOf tellnote)

        Button1.Enabled = False

        thnote.Start()

Sub tellnote()

        Try

            For Each itm In ListBox1.SelectedItems

                Dim cm As New SqlCommand("insert into notes (mto,note) values(@mto,@note)", con)

                cm.Parameters.AddWithValue("@mto", itm)

                cm.Parameters.AddWithValue("@note", al.Text)

                If con.State = ConnectionState.Closed Then

                    con.Open()

                End If

                cm.ExecuteNonQuery()

                MsgBox("تم تنبيه الجميع", MsgBoxStyle.Information, "")

            Next

        Catch ex As Exception

            MsgBox(Err.Description, MsgBoxStyle.Critical, "")

        End Try

        Button1.Enabled = True

    End Sub