Engine中如何更改lyr文件数据源的相对路径

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();