รบกวนช่วยหน่อยครับ ผมเพิ่มข้อมูลจาก Datagridview ลงฐานข้อมูล แต่ทำไมค่าที่บันทึกถึงเป็นค่าแรกหมดเลยครับ

Imports System.Data
Imports System.Data.OleDb

Public Class frm_order
    Dim DR As OleDbDataReader
    Dim DT As DataTable
    Dim DC As New OleDbCommand
    Dim DC1 As New OleDbCommand
    Dim DA As OleDbDataAdapter
    Dim DA1 As OleDbDataAdapter
    Dim DS As New DataSet
    Dim DS1 As New DataSet
    Dim TR As OleDbTransaction
    Dim TR1 As OleDbTransaction
    Dim SAVE As String = ""

    Private Sub frm_order_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        ConnectDB()
        ShowData()
        Formatdatagrid()
        EnableAll()
        autoid()
        txt_sum.Text = "0"
    End Sub

    Sub Reset()
        txt_productid.Clear()
        txt_product.Clear()
        txt_price.Clear()
        txt_qty.Clear()
        txt_cusid.Clear()
        txt_username.Clear()
        GV_ADD.Rows.Clear()
        txt_sum.Text = "0"
    End Sub
    Sub EnableAll()
        add.Enabled = False
        save1.Enabled = False
    End Sub

    Sub ShowData()
        Dim sqlshow As String
        sqlshow = "SELECT * FROM product Order by pro_id ASC "
        DS.Clear()
        DA = New OleDbDataAdapter(sqlshow, CONN)
        DA.Fill(DS, "Product")
        GV.DataSource = DS.Tables("Product")
    End Sub

    Sub Formatdatagrid()
        With GV
            .ReadOnly = True 'สังให้ DataGrid สามารถอ่านได้อย่างเดียว
            If .RowCount > 0 Then
                .Font = New Font("Tahoma", 9, FontStyle.Bold)
                .Columns(0).HeaderText = "รหัสสินค้า"
                .Columns(1).HeaderText = "ชื่อสินค้า"
                .Columns(2).HeaderText = "ราคา"
                .Columns(0).Width = 100
                .Columns(1).Width = 100
                .Columns(2).Width = 80
                .AlternatingRowsDefaultCellStyle.BackColor = Color.White
                .DefaultCellStyle.BackColor = Color.AntiqueWhite
            End If
        End With
    End Sub

    Sub autoid()
        Dim tmpautoid As Integer = 0
        Dim sqlauto As String
        sqlauto = "SELECT order_id From tb_order Order By order_id DESC"
        DC.CommandType = CommandType.Text
        DC.CommandText = sqlauto
        DC.Connection = CONN
        DA = New OleDbDataAdapter(DC)
        DS1.Clear()
        DA.Fill(DS1, "number")
        tmpautoid = (DS1.Tables("number").Rows.Count) + 1
        txt_order.Text = Format("PO" + tmpautoid.ToString("000000000"))
    End Sub

    Sub Add_Data2Grid()

        GV_ADD.AllowUserToAddRows = True
        GV_ADD.Rows.Add()
        GV_ADD.ClearSelection()
        With GV_ADD
            Dim r As Integer = .Rows.Count - 2
            .Rows(r).Cells(0).Value = txt_order.Text.Trim
            .Rows(r).Cells(1).Value = txt_productid.Text.Trim
            .Rows(r).Cells(2).Value = txt_product.Text.Trim
            .Rows(r).Cells(3).Value = txt_price.Text.Trim
            .Rows(r).Cells(4).Value = txt_qty.Text.Trim
            .Rows(r).ReadOnly = True
            .CurrentCell = .Rows(r).Cells(1)
        End With

        GV_ADD.AllowUserToAddRows = False
        txt_productid.Text = String.Empty
        txt_product.Text = String.Empty
        txt_price.Text = String.Empty
        txt_qty.Text = String.Empty
        txt_qty.Focus()
    End Sub

    Private Sub GV_CellContentClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles GV.CellContentClick
        Dim userselectrow As Integer = 0
        userselectrow = GV.CurrentRow.Index
        With GV
            txt_productid.Text = (GV.Item(0, userselectrow)).Value.ToString
            txt_product.Text = (GV.Item(1, userselectrow)).Value.ToString
            txt_price.Text = (GV.Item(2, userselectrow)).Value.ToString
        End With
        add.Enabled = True
        save1.Enabled = True

    End Sub

    Private Sub add_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles add.Click
        SAVE = "ADD"
        If txt_order.Text = String.Empty And txt_productid.Text = String.Empty Or txt_product.Text = String.Empty Or txt_price.Text = String.Empty Or txt_qty.Text = String.Empty Then
            MessageBox.Show("กรุณาเลือกข้อมูลการสั่งซื้อ")
        ElseIf txt_qty.Text = String.Empty Then
            MessageBox.Show("กรุณาใส่จำนวน")
            txt_qty.Focus()
        Else
            Add_Data2Grid()
        End If
        Dim i As Integer
        Dim tmp As Integer = 0
        Dim total As Integer = 0
        Dim count As Integer = GV_ADD.Rows.Count - 1
        For i = 0 To count
            tmp = (CInt(GV_ADD.Rows(i).Cells(3).Value)) * (CInt(GV_ADD.Rows(i).Cells(4).Value))
            total += tmp
            txt_sum.Text = CStr(total)
        Next
    End Sub

    Private Sub save1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles save1.Click
        TR = CONN.BeginTransaction()
        If txt_order.Text = "" Then
            MessageBox.Show("กรุณากรอกรหัสใบสั่งซื้อ")
            txt_order.Focus()
            TR.Rollback()
            Exit Sub
        Else
            Dim sqlsave As String = String.Empty
            Dim sqlsaveline As String = String.Empty
            Dim tmpmsg As String
            Try
                Select Case SAVE
                    Case "ADD"
                        'Header Item ส่วนการเพิ่มข้อมูล ตาราง tb_order
                        sqlsave = "INSERT INTO tb_order VALUES('" & txt_order.Text & "'" & _
                                  ",'" & Now() & "','" & txt_sum.Text & "','A','" & txt_cusid.Text & "')"
                End Select
                If SAVE = "ADD" Then
                    tmpmsg = "คุณต้องการเพิ่มข้อมูลใช่หรือไม่"
                Else
                    tmpmsg = "คุณต้องการแก้ไขข้อมูลใช่หรือไม่"
                End If
                If MessageBox.Show(tmpmsg, "ยืนยัน", MessageBoxButtons.YesNo, MessageBoxIcon.Question, MessageBoxDefaultButton.Button1) = Windows.Forms.DialogResult.Yes Then
                    DC.CommandText = sqlsave
                    DC.CommandType = CommandType.Text
                    DC.Connection = CONN
                    DC.Transaction = TR
                    DA = New OleDbDataAdapter(DC)
                    DA.Fill(DS, "Order")
                    TR.Commit()
                    DS.Clear()
                    MessageBox.Show("เพิ่มใบสั่งซืื้อเรียบร้อย")
                Else
                    TR.Rollback()
                End If

            Catch ex As Exception
                MessageBox.Show("เกิดข้อผิดพลาด", "ตรวจสอบข้อผิดพลาด", MessageBoxButtons.OK, MessageBoxIcon.Error)
                TR.Rollback()
            End Try
            'ตรงช่วงนี้ครับ ----------> Line Item ส่วนการเพิ่มข้อมูล ตาราง orderdetail
            For i = 0 To GV_ADD.Rows.Count - 1
                DC1.Parameters.Add("order", OleDb.OleDbType.VarChar).Value = GV_ADD.Rows(i).Cells(0).Value
                DC1.Parameters.Add("proid", OleDb.OleDbType.VarChar).Value = GV_ADD.Rows(i).Cells(1).Value
                DC1.Parameters.Add("price", OleDb.OleDbType.VarChar).Value = GV_ADD.Rows(i).Cells(4).Value
                sqlsaveline = "insert into orderdetail(order_id,pro_id,order_qty)values(order,proid,price)"
                DC1.CommandText = sqlsaveline
                DC1.CommandType = CommandType.Text
                DC1.Connection = CONN
                DC1.ExecuteNonQuery()
            Next
            ShowData()
            Formatdatagrid()
            EnableAll()
            autoid()
            Reset()
        End If
    End Sub

    Private Sub cancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cancel.Click
        Reset()
    End Sub

    Private Sub back_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles back.Click
        Me.Close()
    End Sub
End Class