لماذا يخرج هذا الخطاء
هذه هو الكود
Private Sub bt1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bt1.Click, bt2.Click, bt3.Click, bt4.Click, bt5.Click, bt6.Click, bt7.Click, bt8.Click, bt9.Click, bt10.Click, bt11.Click, bt12.Click, bt13.Click, bt14.Click, bt15.Click, bt16.Click, bt17.Click, bt18.Click, bt19.Click, bt20.Click
Dim btn As Button = DirectCast(sender, Button)
opencon()
Dim da As New SqlDataAdapter("select * from tb_Item ", con)
Dim ds As New DataSet
da.Fill(ds, "tb_Item")
' ds.Dispose()
con.Close()
Dim newitem As Boolean = True
For i = 0 To dt.Rows.Count - 1
If sender.tag = dt.Rows(i).Item("id_a") And btn.Text = dt.Rows(i).Item("kind") Then
dt.Rows(i).Item("Count") = dt.Rows(i).Item("Count") + 1
dt.Rows(i).Item("total") = dt.Rows(i).Item("count") * dt.Rows(i).Item("sill_price")
newitem = False
Exit For
End If
Next
If newitem = True Then
هنا يخرج الخطاء dt.Rows.Add(sender.tag, btn.Text, ds.Tables("tb_Item").Rows(sender.tag)("sell_price_item"), 1, ds.Tables("tb_Item").Rows(sender.tag)("sell_price_item"))
End If
FillGrid(DataGridView1, dt)
fill_total()
End Sub