BrightIdeasSoftware.ObjectListView.GetPreviousItem C# (CSharp) Method

        public virtual OLVListItem GetPreviousItem(OLVListItem itemToFind)
        {
            if (this.ShowGroups) {
                OLVListItem previousItem = null;
                foreach (ListViewGroup group in this.Groups) {
                    foreach (OLVListItem lvi in group.Items) {
                        if (lvi == itemToFind)
                            return previousItem;

                        previousItem = lvi;
                    }
                }
                return itemToFind == null ? previousItem : null;
            }
            if (this.GetItemCount() == 0)
                return null;
            if (itemToFind == null)
                return this.GetItem(this.GetItemCount() - 1);
            if (itemToFind.Index == 0)
                return null;
            return this.GetItem(itemToFind.Index - 1);
        }