Can't get the datagridview to update after insert.

Private Sub CUDAreadings_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        'TODO: This line of code loads data into the 'MubsDataSet.tblReadings' table. You can move, or remove it, as needed.

        UpdateDataGrid()

        ClearTextBoxes()
        tbReadMeterNo.Focus()
        btnAdd.Enabled = True
    End Sub



    Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click
        Try
            Call connection()

            Dim cm = New OleDb.OleDbCommand
            With cm
                .Connection = con  'dcMubs
                .CommandType = CommandType.Text

                .CommandText = "INSERT INTO tblReadings (ReadMeterNo, ReadCusNo, ReadDate, Reading, ReadUsage, " &
                                         "ReadType, ReadMethod, ReadTech, ReadPostDate) " &
                                        "VALUES (@ReadMeterNo, @ReadCusNo, @ReadDate, @Reading, @ReadUsage, " &
                                       "@ReadType, @ReadMethod, @ReadTech, @ReadPostDate) "
                cm.Parameters.Clear()

                cm.Parameters.AddWithValue("@ReadMeterNo", Me.tbReadMeterNo.Text)
                cm.Parameters.AddWithValue("@ReadCusNo", Me.tbReadCusNo.Text)
                cm.Parameters.AddWithValue("@ReadDate", Me.dtpReadDate.Value.Date)
                cm.Parameters.AddWithValue("@Reading", Me.tbReading.Text)
                cm.Parameters.AddWithValue("@ReadingUsage", Me.tbUnitsUsed.Text)
                cm.Parameters.AddWithValue("@ReadType", Me.tbReadType.Text)
                cm.Parameters.AddWithValue("@ReadMethod", "Manual")
                cm.Parameters.AddWithValue("@ReadTech", Me.tbReadTech.Text)
                cm.Parameters.AddWithValue("@ReadPostDate", DBNull.Value)

                cm.ExecuteNonQuery()

                'MsgBox("Reading Record UPDATED.", MsgBoxStyle.Information)
            End With

        Catch ex As Exception
            MsgBox(ex.Message, MsgBoxStyle.Critical)
            errornumber = 160 'Assigned error number for logging & debugging.
            clsLogFile = New LogFile(ex.Message, errornumber)
        End Try

        If tbReadType.Text <> lastReadType Then
            lastReadType = tbReadType.Text
        End If

        Call ClearTextBoxes()
        dtpReadDate.TabStop = False
        tbReadTech.TabStop = False
        tbReadMeterNo.Focus()
        UpdateDataGrid()

    End Sub

    Private Sub UpdateDataGrid()
        Try
            'clear out the datasource for the Grid view
            Me.DataGridView1.DataSource = Nothing
            'refill the table adapter from the dataset table 
            Me.TblReadingsTableAdapter.Fill(Me.MubsDataSet.tblReadings)
            'reset the datasource from the binding source
            Me.DataGridView1.DataSource = Me.TblReadingsBindingSource
            'should redraw with the new data
            Me.DataGridView1.Update()
            Me.DataGridView1.RefreshEdit()

        Catch ex As Exception
            MsgBox(ex.Message, MsgBoxStyle.Critical)
            errornumber = 161 'Assigned error number for logging & debugging.
            clsLogFile = New LogFile(ex.Message, errornumber)
        End Try

    End Sub