or
GridTableView nestedView1 = (GridTableView)parentItem.ChildItem.NestedTableViews[0]; foreach (GridDataItem childItem1 in nestedView1.Items) { if (childItem1.OwnerTableView.Name == "Products") { string selectedText= childItem1["ProductId"].Text; GridEditableItem NewItem1 = (GridEditableItem)e.Item; TableCell NewProdId = NewItem1["ProductId"]; string NewTxtProdId = (NewProdId.Controls[0] as DropDownList).SelectedValue; string selectedValue=""; //Find a way to get selectedvalue of childItem1 if (selectedValue == NewTxtProdId) { DisplayMessage("This product id is already selected."); e.Canceled = true; } } }