VC+AO想得到某个图层具体的SYMBOL??

<P>CString layerName;<BR> ILayerPtr pLayer;<BR> IFeatureLayerPtr pFLayer;<BR> IGeoFeatureLayerPtr pGFLayer;<BR> IFeatureRendererPtr pFRender;<BR> ISimpleRendererPtr pSRender;<BR> ISymbolPtr pSymbol;</P>
<P>pLayer=GetLayer2(m_mapMain,layerName);<BR> ASSERT(pLayer!=NULL);<BR> pFLayer=pLayer;<BR> pGFLayer=pFLayer;<BR> ASSERT(pGFLayer!=NULL);<BR> pGFLayer->get_Renderer(;pFRender);<BR> pSRender=pFRender;<BR> pSRender->get_Symbol(;pSymbol);</P>
<P>现在只是得到了ISymbol接口,还不知道具体的SYMBOL,比如是ISimpleMarkerSymbol还是ICharacterMarkerSymbol还是ISimpleLineSymbol等</P>
<P>怎么办,各位大侠,多多xi</P>

<P>FeatureRenderer 有什么用？</P>
<P>我一直没明白</P>