1、通过AIS_InteractiveContext的函数访问当前选择的图形

hAISContext->InitSelected();
hAISContext->MoreSelected();
hAISContext->NextSelected()；
hAISContext->SelectedShape()；

其中hAISContext->SelectedShape()通过StdSelect_BrepOwner来获取TopoDS_Shape，具体的参看源码即可

2、示例

• 绘制一个box，并激活box的顶点、边、面的选择模式

  	//create box for test
  	BRepPrimAPI_MakeBox mkBox(gp_Pnt(0, 0, 0), 10, 20, 30);
  	TopoDS_Shape aShpae = mkBox.Shape();
  	Handle(AIS_Shape) hBoxShape = new AIS_Shape(aShpae);
  	myAISContext->Display(hBoxShape, Standard_True);
  
  	myAISContext->Deactivate(hBoxShape);
  	myAISContext->Activate(hBoxShape, AIS_Shape::SelectionMode(TopAbs_FACE));
  	myAISContext->Activate(hBoxShape, AIS_Shape::SelectionMode(TopAbs_EDGE));
  	myAISContext->Activate(hBoxShape, AIS_Shape::SelectionMode(TopAbs_VERTEX));
  

• 选择的处理

  void COCTView::OnBtnTestSelect()
  {
  	auto hAISContext = GetDocument()->GetAISContext();
  	if (!hAISContext)
  	{
  		return;
  	}
  
  	for (hAISContext->InitSelected(); hAISContext->MoreSelected();
  		hAISContext->NextSelected())
  	{
  		TopoDS_Shape aShape = hAISContext->SelectedShape();
  		if (aShape.IsNull()) continue;
  
  		switch (aShape.ShapeType())
  		{
  		case TopAbs_ShapeEnum::TopAbs_VERTEX:
  		{
  			TopoDS_Vertex aVertex = TopoDS::Vertex(aShape);
  			AfxMessageBox(_T("选中一个点"));
  			break;
  		}
  		case TopAbs_ShapeEnum::TopAbs_EDGE:
  		{
  			AfxMessageBox(_T("选中一条边"));
  			break;
  		}
  		case TopAbs_ShapeEnum::TopAbs_FACE:
  		{
  			AfxMessageBox(_T("选中一个面"));
  			break;
  		}
  		//其他略
  		}
  	}
  }
  

3、演示