Add and Update Data Button

connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\invData.mdb;"
        cnn = New OleDbConnection(connectionString)
        Dim cmd As New OleDb.OleDbCommand
        If Not cnn.State = ConnectionState.Open Then
            'open connection if it is not yet open
            cnn.Open()
        End If
 
        cmd.Connection = cnn
        'check whether add new or update
        If Me.TextBox1.Tag & "" = "" Then
            'add new 
            'add data to table
            cmd.CommandText = "INSERT INTO NTIdb(ID, Status, DateDeliver, Client, POrder, StoreCode, StoreType, ProdUsage, ProdCategory, Brand, Description, Quantity, MainUnitSerial, HDD1, HDD2, OpticalDrive, Monitor, Keyboard, NetAdaptor, ProdKey, WTYEnt, AccExec, SalesOrder, SalesInv, DReceipt, ReceivedBy, WayBill, DueDate) " & _
                " VALUES(" & TextBox1.Text & ",'" & ComboBox1.SelectedItem() & "','" & _
                           DateTimePicker1.Value() & "','" & TextBox2.Text & "','" & _
                           TextBox3.Text & "', '" & TextBox4.Text & "', '" & TextBox5.Text & "','" & _
                           TextBox6.Text & "', '" & TextBox7.Text & "', '" & TextBox8.Text & "','" & _
                           TextBox9.Text & "', '" & NumericUpDown1.Value() & "', '" & TextBox10.Text & "','" & _
                           TextBox11.Text & "', '" & TextBox12.Text & "', '" & TextBox13.Text & "', '" & _
                           TextBox14.Text & "', '" & TextBox15.Text & "', '" & TextBox16.Text & "', '" & _
                           TextBox17.Text & "', '" & TextBox18.Text & "', '" & TextBox19.Text & "', '" & _
                           TextBox20.Text & "', '" & TextBox21.Text & "', '" & TextBox22.Text & "', '" & _
                           TextBox23.Text & "', '" & TextBox24.Text & "', '" & DateTimePicker2.Value() & "')"
 
            adptr.InsertCommand = New OleDbCommand(cmd.CommandText, cnn)
            cmd.ExecuteNonQuery()
        Else
            'update data in table
            cmd.CommandText = "UPDATE NTIdb " & _
                        " SET ID=" & TextBox1.Text & _
                        ", Status='" & ComboBox1.SelectedItem() & "'" & _
                        ", DateDeliver='" & DateTimePicker1.Value() & "'" & _
                        ", Client='" & TextBox2.Text & "'" & _
                        ", POrder='" & TextBox3.Text & "'" & _
                        ", StoreCode='" & TextBox4.Text & "'" & _
                        ", StoreType='" & TextBox5.Text & "'" & _
                        ", ProdUsage='" & TextBox6.Text & "'" & _
                        ", ProdCategory='" & TextBox7.Text & "'" & _
                        ", Brand='" & TextBox8.Text & "'" & _
                        ", Descrption='" & TextBox9.Text & "'" & _
                        ", Quantity='" & NumericUpDown1.Value() & "'" & _
                        ", MainUnitSerial='" & TextBox10.Text & "'" & _
                        ", HDD1='" & TextBox11.Text & "'" & _
                        ", HDD2='" & TextBox12.Text & "'" & _
                        ", OpticalDrive='" & TextBox13.Text & "'" & _
                        ", Monitor='" & TextBox14.Text & "'" & _
                        ", Keyboard='" & TextBox15.Text & "'" & _
                        ", NetAdaptor='" & TextBox16.Text & "'" & _
                        ", ProdKey='" & TextBox17.Text & "'" & _
                        ", WTYEnt='" & TextBox18.Text & "'" & _
                        ", AccExec='" & TextBox19.Text & "'" & _
                        ", SalesOrder='" & TextBox20.Text & "'" & _
                        ", SalesInv='" & TextBox21.Text & "'" & _
                        ", DReceipt='" & TextBox22.Text & "'" & _
                        ", ReceibedBy='" & TextBox23.Text & "'" & _
                        ", Waybill='" & TextBox24.Text & "'" & _
                        ", DueDate='" & DateTimePicker2.Value() & "'" & _
                        ", WHERE ID=" & TextBox1.Tag()
            cmd.ExecuteNonQuery()
        End If
        'refresh data in list
        RefreshData()
        'clear form
        Me.Button5.PerformClick()
 
        'close connection
        cnn.Close()
 
        '//To view Client
        connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\invData.mdb;"
 
        Dim ds1 As New DataSet
        Dim sql1 As String = "Select Client from NTIdb"
        cnn = New OleDbConnection(connectionString)
 
        Try
            cnn.Open()
            adptr = New OleDbDataAdapter(sql1, cnn)
            adptr.Fill(ds1)
 
            For a = 0 To ds1.Tables(0).Rows.Count - 1
                ComboBox2.Items.Add(ds1.Tables(0).Rows(a).Item(0))
            Next
 
            adptr.Dispose()
            cnn.Close()
        Catch ex As Exception
            MsgBox(ex.ToString)
        End Try
 
        'get data into list
        Me.RefreshData()
 
        If TextBox2.Text = sql1 Then
            TextBox2.Visible = False
            ComboBox2.Visible = True
        End If