C# AE 符号选择器

using ESRI.ArcGIS.Display;
using ESRI.ArcGIS.DisplayUI
 
private esriTOCControlItem toccItem = esriTOCControlItem.esriTOCControlItemNone;
        private ILayer iLayer = null;
        private IBasicMap iBasicMap = null;
        private void axTOCControl1_OnDoubleClick(object sender, ITOCControlEvents_OnDoubleClickEvent e)
        {
            object unk = null;
            object data = null;
            if (e.button == )
            {
                axTOCControl1.HitTest(e.x, e.y, ref toccItem, ref iBasicMap, ref iLayer, ref unk, ref data);
                System.Drawing.Point pos = new System.Drawing.Point(e.x, e.y);
                if (this.toccItem == esriTOCControlItem.esriTOCControlItemLegendClass)
                {
                    ESRI.ArcGIS.Carto.ILegendClass pLC = new LegendClassClass();
                    ESRI.ArcGIS.Carto.ILegendGroup pLG = new LegendGroupClass();
                    if (unk is ILegendGroup)
                    {
                        pLG = (ILegendGroup) unk;
                    }
                    pLC = pLG.get_Class((int) data);
                    ISymbol pSym;
                    pSym = pLC.Symbol;
                    ESRI.ArcGIS.DisplayUI.ISymbolSelector pSS = new ESRI.ArcGIS.DisplayUI.SymbolSelectorClass();
                    bool bOK = false;
                    pSS.AddSymbol(pSym);
                    bOK = pSS.SelectSymbol();
                    if (bOK)
                    {
                        pLC.Symbol = pSS.GetSymbolAt();
                    }
                    this.axMapControl1.ActiveView.Refresh();
                    this.axTOCControl1.Refresh();
                }
            }
        }

双击axTocControl弹出符号选择器。