如何在CreateView的form_valid方法中引发错误

In a Django project, I have a view (cloud), type: CreateView. This view has a inlineformset_factory. It works. But, if i submit the form with a error (look at "messages.error" below), the page is redirected to project.get_absolute_url(). The problem is: the form content back empty. I know thats because the HttpResponseRedirect.In a Django project, I have a view (cloud), typ