Engine中怎么更改lyr文件数据源的相对路径

以下是使用relativebase存储layerfile的代码，如果需要修改数据源只要修改ILayer即可：

string folderpath = @E:相对路径;string layerfilepath = @E:相对路径layer;ILayer layer = axMapControl1.get_Layer(0);IDataLayer2 pDataLayer = layer as IDataLayer2; pDataLayer.RelativeBase = folderpath + + layer.Name;ILayerFile pLayerFile = new LayerFileClass(); pLayerFile.New(layerfilepath + .lyr);pLayerFile.ReplaceContents(layer); pLayerFile.Save();