protected override IFeatureRenderer Apply()
        {
            ICompositeSymbol sym = (_layer.Renderer as SimpleFeatureRenderer).Symbol as ICompositeSymbol;

            if (listBox1.Items.Count > 0)
            {
                if (sym == null)
                {
                    sym = new CompositeSymbol();
                }
                else
                {
                    sym.Symbols.Clear();
                }
                foreach (SymbolNamePair p in listBox1.Items)
                {
                    sym.Symbols.Add(p.Symbol);
                }
            }
            return(_layer.Renderer);
        }
        protected override void SetLayerAfter()
        {
            if (_layer == null)
            {
                return;
            }
            ISymbol _symbol = null;

            if (_layer.Renderer is SimpleFeatureRenderer)
            {
                _symbol = (_layer.Renderer as SimpleFeatureRenderer).Symbol;
            }
            if (_symbol == null || !(_symbol is ICompositeSymbol))
            {
                _symbol = new CompositeSymbol();
            }
            if (_layer.Renderer != null)
            {
                _layer.Renderer.Dispose();
            }
            _layer.Renderer = new SimpleFeatureRenderer(_symbol);
            LoadOldSymbols(_symbol as ICompositeSymbol);
        }