Django edit form based on add form?

If you are extending your form from a ModelForm, use the instance keyword argument. Here we pass either an existing instance or a new one, depending on whether we're editing or adding an existing article. In both cases the author field is set on the instance, so commit=False is not required. Note also that I'm assuming only the author may edit their own articles, hence the HttpResponseForbidden response.

from django.http import HttpResponseForbiddenfrom django.shortcuts import get_object_or_404, redirect, render, reverse@login_requireddef edit(request, id=None, template_name='article_edit_template.html'):    if id:        article = get_object_or_404(Article, pk=id)        if article.author != request.user:            return HttpResponseForbidden()    else:        article = Article(author=request.user)    form = ArticleForm(request.POST or None, instance=article)    if request.POST and form.is_valid():        form.save()        # Save was successful, so redirect to another page        redirect_url = reverse(article_save_success)        return redirect(redirect_url)    return render(request, template_name, {        'form': form    })

And in your urls.py:

(r'^article/new/$', views.edit, {}, 'article_new'),(r'^article/edit/(?P<id>\d+)/$', views.edit, {}, 'article_edit'),

The same edit view is used for both adds and edits, but only the edit url pattern passes an id to the view. To make this work well with your form you'll need to omit the author field from the form:

class ArticleForm(forms.ModelForm):    class Meta:        model = Article        exclude = ('author',)

You can have hidden ID field in form and for edit form it will be passed with the form for add form you can set it in req.POST e.g.

formData =  req.POST.copy()formData['id'] = getNewID()

and pass that formData to form