how about add first the row then update the items in the ComboBoxColumn
Dim dtgCol As DataGridViewComboBoxCell
Dim row As String()
row = New String() {"0", "1"}
dtgView.Rows.Add(row)
dtgCol = dtgView.Rows(0).Cells(2)
dtgCol.Items.Add("comboitem1")
dtgCol.Items.Add("comboitem2")
row = New String() {"2", "3"}
dtgView.Rows.Add(row)
dtgCol = dtgView.Rows(0).Cells(2)
dtgCol.Items.Add("comboitem1")
dtgCol.Items.Add("comboitem2")
dtgCol.Items.Add("comboitem3")
this is just my idea.. I already done this... hope this helps