AIA.UnitManager.UpdateSelectionList C# (CSharp) Method

        public void UpdateSelectionList(Rectangle SelectionBox)
        {
            for (int i = 0; i < mUnits.Count(); i++)
            {
                //If selection box over units and building not in selection list add to list
                if (SelectionBox.Intersects(mUnits[i].PosRect) && !m_lSelectedUnits.Contains(mUnits[i]))
                {
                    m_lSelectedUnits.Add(mUnits[i]);
                }
                if (!SelectionBox.Intersects(mUnits[i].PosRect) && m_lSelectedUnits.Contains(mUnits[i]))
                {
                    m_lSelectedUnits.Remove(mUnits[i]);
                }

                if (m_lSelectedUnits.Contains(mUnits[i]))
                {
                    mUnits[i].Colour = Color.Red;
                }
                else
                {
                    mUnits[i].Colour = Color.White;
                }
            }
        }