VitNX_ListView.ToggleItem Method

public void ToggleItem(int index)
 {
     if (_selectedIndices.Contains(index))
     {
         _selectedIndices.Remove(index);
 
         // If we just removed both the anchor start AND end then reset them
         if (_anchoredItemStart == index && _anchoredItemEnd == index)
         {
             if (_selectedIndices.Count > 0)
             {
                 _anchoredItemStart = _selectedIndices[0];
                 _anchoredItemEnd = _selectedIndices[0];
             }
             else
             {
                 _anchoredItemStart = -1;
                 _anchoredItemEnd = -1;
             }
         }
 
         // If we just removed the anchor start then update it accordingly
         if (_anchoredItemStart == index)
         {
             if (_anchoredItemEnd < index)
                 _anchoredItemStart = index - 1;
             else if (_anchoredItemEnd > index)
                 _anchoredItemStart = index + 1;
             else
                 _anchoredItemStart = _anchoredItemEnd;
         }
 
         // If we just removed the anchor end then update it accordingly
         if (_anchoredItemEnd == index)
         {
             if (_anchoredItemStart < index)
                 _anchoredItemEnd = index - 1;
             else if (_anchoredItemStart > index)
                 _anchoredItemEnd = index + 1;
             else
                 _anchoredItemEnd = _anchoredItemStart;
         }
     }
     else
     {
         _selectedIndices.Add(index);
         _anchoredItemStart = index;
         _anchoredItemEnd = index;
     }
 
     if (SelectedIndicesChanged != null)
         SelectedIndicesChanged(this, null);
 
     Invalidate();
 }