hide command buttons/links issue

[El]

I managed it to hides Add New Record button but only the one at the top. The other one at the bottom remains visible :(

if (e.Item is GridCommandItem)
                    {
                        GridCommandItem cmdItem = (GridCommandItem)RadGrid1.MasterTableView.GetItems(GridItemType.CommandItem)[0];
                        ((LinkButton)cmdItem.FindControl("InitInsertButton")).Visible = false;
                    }

Also how do i hide the delete button? I tried the next but it didn't work properly.

if (e.Item is GridDataItem)
                    {
                        GridDataItem item = (GridDataItem)e.Item;
                        LinkButton editButton = (LinkButton)item.FindControl("EditButton");
                        editButton.Visible = false;
                        //LinkButton deleteButton = (LinkButton)item.FindControl("DeleteButton");
                        //deleteButton.Visible = false;
                    }

the Edit button gets hidden but the delete throws an exception "Object reference not set to an instance of an object".