IUniqueValueRenderer pUniqueValueRenderer = pFeatureLayer.Renderer as IUniqueValueRenderer; ISymbol pSymbol = pUniqueValueRenderer.get_Symbol("某个值");
IUniqueValueRenderer pUniqueValueRenderer = pFeatureLayer.Renderer as IUniqueValueRenderer; ISymbol pSymbol = pUniqueValueRenderer.get_Symbol("某个值");