如何访问 VTK 的 class 枚举字段

How to access VTK's class enumeration field

我在尝试访问以下代码中的枚举字段时遇到问题。

    vtkSmartPointer<vtkGenericDataObjectReader> reader =
        vtkSmartPointer<vtkGenericDataObjectReader>::New();
    reader->SetFileName(file_name);
    reader->Update();

    vtkSmartPointer<vtkDataObject> vtk_data = reader->GetOutput();


    vtkSmartPointer<vtkFieldData> points = 
        vtk_data->GetAttributesAsFieldData(vtkDataObject::AttributeTypes.POINT);
    //points->PrintSelf(cout, 0);

但是我收到以下错误:

error: expected primary-expression before ‘int’ vtk_data->GetAttributesAsFieldData(int(vtkDataObject::AttributeTypes.POINT));

对我来说(使用 GCC 8.1)以下编译没有任何错误。

#include <vtkDataObject.h>

int main(){
    auto a = vtkDataObject::AttributeTypes::POINT;    
    return 0;
}