กดปุ่ม button เพื่อที่จะย้ายข้อมูลจากตาราง A ไป B พร้อมลบข้อมูลจากตาราง A ทิ้ง แจ้ง object reference not set to an instance of an object

Private Sub btnOK_Click(sender As Object, e As EventArgs) Handles btnOK.Click

        open_database()
        Try

            If Label45.Text = "0" Then
                MessageBox.Show("Error! Number less than rows count ", "Result", MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1)
                tb01.Clear()
                tb01.Focus()

            ElseIf tb01.Text = Nothing Then
                MessageBox.Show("Error! กรุณาป้อนจำนวนที่ต้องการให้ถูกต้อง", "ผลการตรวจสอบ", MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1)
                tb01.Clear()
                tb01.Focus()

            ElseIf CInt(tb01.Text) = 0 Then
                MessageBox.Show("Error! กรุณาป้อนจำนวนที่ต้องการให้ถูกต้อง", "ผลการตรวจสอบ", MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1)
                tb01.Clear()
                tb01.Focus()

            ElseIf (tb01.Text) <> "" AndAlso (txtSearch.Text) = Nothing Then
                MessageBox.Show("ผิดพลาด! ไม่สามารถจองได้หากยังไม่ได้เลือกวัตถุดิบ/Error! You have to select Material", "ผลการตรวจสอบ", MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1)
                tb01.Clear()
                tb01.Focus()

            ElseIf CInt(tb01.Text) > 100 Then
                MessageBox.Show("Error! Number less than 100", "Result", MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1)
                tb01.Clear()
                tb01.Focus()

            ElseIf (tb01.Text) > dgv02.Rows.Count Then
                MessageBox.Show("Error! Number less than rows count", "Result", MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1)
                tb01.Clear()
                tb01.Focus()
            Else

                Dim start As Integer = dgv02.CurrentCell.RowIndex
                For i As Integer = start To (start + CInt(tb01.Text)) - 1

                    If Not dgv02.Rows(i).IsNewRow Then
                        sql = "insert into reservation1 (id, product_id, product_name, product_warehouse," & _
                            "product_amount, product_qty, product_lotno, product_color, product_date, mat_return, " & _
                            "boi, location, product_datereservation, expired_date, expired_ready, expired_warning) " & _
                            "values (@id, @product_id, @product_name, @product_warehouse, @product_amount, @product_qty, @product_lotno, " & _
                            "@product_color, @product_date, @mat_return, @boi, @location, @product_datereservation, " & _
                            "@expired_date, @expired_ready, @expired_warning)"
                        sql &= "delete from in_stock1 where product_id='" & dgv02.Rows(i).Cells(1).Value & "';"

                        cmd = New System.Data.SqlClient.SqlCommand(sql, cn)
                        With cmd
                            .Parameters.Add(New SqlParameter("@id", dgv02.Rows(i).Cells(0).Value))
                            .Parameters.Add(New SqlParameter("@product_id", dgv02.Rows(i).Cells(1).Value))
                            .Parameters.Add(New SqlParameter("@product_name", dgv02.Rows(i).Cells(2).Value))
                            .Parameters.Add(New SqlParameter("@product_warehouse", dgv02.Rows(i).Cells(3).Value))
                            .Parameters.Add(New SqlParameter("@product_amount", dgv02.Rows(i).Cells(4).Value))
                            .Parameters.Add(New SqlParameter("@product_qty", dgv02.Rows(i).Cells(5).Value))
                            .Parameters.Add(New SqlParameter("@product_lotno", dgv02.Rows(i).Cells(6).Value))
                            .Parameters.Add(New SqlParameter("@product_color", dgv02.Rows(i).Cells(7).Value))
                            .Parameters.Add(New SqlParameter("@product_date", dgv02.Rows(i).Cells(8).Value))
                            .Parameters.Add(New SqlParameter("@mat_return", dgv02.Rows(i).Cells(9).Value))
                            .Parameters.Add(New SqlParameter("@boi", dgv02.Rows(i).Cells(10).Value))
                            .Parameters.Add(New SqlParameter("@location", dgv02.Rows(i).Cells(11).Value))
                            .Parameters.Add(New SqlParameter("@product_datereservation", DateTime.Now.ToString("yyyy-MM-dd")))
                            .Parameters.Add(New SqlParameter("@expired_date", dgv02.Rows(i).Cells(12).Value))
                            .Parameters.Add(New SqlParameter("@expired_ready", dgv02.Rows(i).Cells(13).Value))
                            .Parameters.Add(New SqlParameter("@expired_warning", dgv02.Rows(i).Cells(14).Value))
                        End With
                        cmd.ExecuteNonQuery()
                    End If
                Next
                loaddb("select * from in_stock1 where product_name='" & txtSearch.Text & "' and product_color='" & txtColorSearch.Text & "'")
                loaddbdgv2("select * from in_stock1 where product_name='" & txtSearch.Text & "' and product_color='" & txtColorSearch.Text & "'")
            End If

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
        cn.Close()
        load_dgv01()

        load_dgv2()
        sumDgv002()
        tb01.Clear()
        tb01.Focus()
        'dgv02.Sort(dgv02.Columns(8), System.ComponentModel.ListSortDirection.Ascending)

        dgv2.NewRowIndex.ToString(txtSearch.Text)
        For i = dgv2.RowCount - 1 To 0 Step -1
            If dgv2.Rows.Item(i).Cells(0).Value = txtSearch.Text And dgv2.Rows.Item(i).Cells(1).Value = txtColorSearch.Text And dgv2.Rows.Item(i).Cells(1).Value = txtType.Text Then

                dgv2.Rows(i).Selected = True
                Me.dgv2.CurrentCell = Me.dgv2.Rows(i).Cells(0)
            End If
        Next

        txtSearch.Text = ""
        txtColorSearch.Text = ""
        txtType.Text = ""

    End Sub