[IfcEnvironmentalImpactValue.UserDefinedCategory property UserDefinedCategory public IfcLabel UserDefinedCategory { get; set; } 也可以看看 class IfcLabel class IfcEnvironmentalImpactValue 命名空间 Aspose.CAD.FileFormats.Ifc.IFC2X3.Entities 部件 Aspose.CAD]