说明：  到目前为止，我知道的能生成缓冲区的有两种方法，一个是ITopologicalOperator.Buffer，另一个是使用ESRI.ArcGIS.AnalysisTools.Buffer。前者争对的是一个单独的IGeometry对象，后者则是对整个图层。
(So far, I know will be able to create a Buffer zone have two kinds of methods, one is ITopologicalOperator. Buffer, and the other is to use ESRI. ArcGIS. AnalysisTools. Buffer. The former vying for a single IGeometry object, the latter is to the layer.)