How to use datagrid?

Question

I have inserted 4 columns (barcode, name, quantity and price).
When I scan any particular barcode for the 2nd time I don't want the data duplicated, just the quantity increased.
So far I have just coded

Private Sub CTbarcode_KeyPress(KeyAscii As Integer)
    If KeyAscii = 13 Then
        Main.MSAadodc1.Recordset.Find "BARCODE='" & CTbarcode.Text & "'", , adSearchForward, 1
        If Not Main.MSAadodc1.Recordset.EOF Then
            CAadodc1.Recordset.Find "BARCODE='" & CTbarcode.Text & "'", , adSearchForward, 1
            If CAadodc1.Recordset.EOF Then
                CTproduct.Text = Main.MSAadodc1.Recordset!PRODUCT
                CTprice.Text = Main.MSAadodc1.Recordset!PRICE
                CTquantity.Text = "1"
                CAadodc1.Recordset.AddNew
                CAadodc1.Recordset!tbarcode = CTbarcode.Text
                CAadodc1.Recordset!tproduct = CTproduct.Text
                CAadodc1.Recordset!tquantity = CTquantity.Text
                CAadodc1.Recordset!tprice = CTprice.Text
                CAadodc1.Recordset!tdiscount = CTquantity.Text
                CAadodc1.Recordset!ttotalprice = Val(CTprice.Text * CTquantity.Text) - CTquantity.Text
                CTbarcode.SetFocus
            Else
                CAadodc1.Recordset!tquantity = Val(CAadodc1.Recordset!tquantity + 1)
                CTbarcode.SetFocus
                CAadodc1.Refresh
            End If
        Else
            MsgBox "Data Not Found!", vbOKOnly + vbCritical, "Unknown!"
            CTbarcode.Text = ""
        End If
    End If
End Sub

Answer 1

Private Sub CTbarcode_KeyPress(KeyAscii As Integer)
    If KeyAscii = 13 Then
        Main.MSAadodc1.Recordset.Find "BARCODE='" & CTbarcode.Text & "'", , adSearchForward, 1
        If Not Main.MSAadodc1.Recordset.EOF Then
            CAadodc1.Recordset.Find "tbarcode='" & CTbarcode.Text & "'", , adSearchForward, 1
            If CAadodc1.Recordset.EOF Then
                CTproduct.Text = Main.MSAadodc1.Recordset!PRODUCT
                CTprice.Text = Main.MSAadodc1.Recordset!PRICE
                CTquantity.Text = "1"
                CAadodc1.Recordset.AddNew
                CAadodc1.Recordset!tbarcode = CTbarcode.Text
                CAadodc1.Recordset!tproduct = CTproduct.Text
                CAadodc1.Recordset!tquantity = CTquantity.Text
                CAadodc1.Recordset!tprice = CTprice.Text
                CAadodc1.Recordset!tdiscount = 0
                CAadodc1.Recordset!ttotalprice = Val(CTprice.Text * CTquantity.Text) - CTquantity.Text
                CTbarcode.SetFocus
                CTbarcode.Text = ""
                CTprice.Text = ""
                CTproduct.Text = ""
                CTquantity.Text = ""
            Else
                CAadodc1.Recordset!tquantity = CAadodc1.Recordset!tquantity + 1
                CAadodc1.Recordset!tdiscount = 0
                CAadodc1.Recordset!ttotalprice = Val(CAadodc1.Recordset!tprice * CAadodc1.Recordset!tquantity - CAadodc1.Recordset!tdiscount)
                CAadodc1.Recordset.Update
                CTbarcode.SetFocus
                CTbarcode.Text = ""
                CTprice.Text = ""
                CTproduct.Text = ""
                CTquantity.Text = ""
            End If
        Else
            MsgBox "Data Not Found!", vbOKOnly + vbCritical, "Unknown!"
            CTbarcode.Text = ""
        End If
    End If
End Sub