获取CompoundStructureLayer Face

Question

使用Revit API检索CompoundStructureLayer的面是否有任何方法？

这是我目前的“提取层”代码：

CompoundStructure compoundStructure = wall.WallType.GetCompoundStructure();

IList<CompoundStructureLayer> layers = compoundStructure.GetLayers();

foreach (CompoundStructureLayer layer in layers)
{
    // Retrieve Faces
}

这是当前的get faces代码：

GeometryElement geo = wall.get_Geometry(opt);
GeometryObjectArray objects = geo.Objects;
foreach (GeometryObject obj in objects)
{
    Solid solid = obj as Solid;
    if (solid != null)
    {
        FaceArray fa = solid.Faces;
        // Do face stuff
    }
}

我无法将CompoundStructureLayer转换为Element类型..如何提取面部信息？