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diff --git a/docs/newforms.txt b/docs/newforms.txt index 41930c0605..ad3f81cb6c 100644 --- a/docs/newforms.txt +++ b/docs/newforms.txt @@ -2168,6 +2168,317 @@ layout -- simply add a media declaration to the form:: <script type="text/javascript" src="http://media.example.com/actions.js"></script> <script type="text/javascript" src="http://media.example.com/whizbang.js"></script> +Formsets +======== + +A formset is a layer of abstraction to working with multiple forms on the same +page. It can be best compared to a data grid. Let's say you have the following +form:: + + >>> from django import newforms as forms + >>> class ArticleForm(forms.Form): + ... title = forms.CharField() + ... pub_date = forms.DateField() + +You might want to allow the user to create several articles at once. To create +a formset of ``ArticleForm``s you would do:: + + >>> from django.newforms.formsets import formset_factory + >>> ArticleFormSet = formset_factory(ArticleForm) + +You now have created a formset named ``ArticleFormSet``. The formset gives you +the ability to iterate over the forms in the formset and display them as you +would with a regular form:: + + >>> formset = ArticleFormSet() + >>> for form in formset.forms: + ... print form.as_table() + <tr><th><label for="id_form-0-title">Title:</label></th><td><input type="text" name="form-0-title" id="id_form-0-title" /></td></tr> + <tr><th><label for="id_form-0-pub_date">Pub date:</label></th><td><input type="text" name="form-0-pub_date" id="id_form-0-pub_date" /></td></tr> + +As you can see it only displayed one form. This is because by default the +``formset_factory`` defines one extra form. This can be controlled with the +``extra`` parameter:: + + >>> ArticleFormSet = formset_factory(ArticleForm, extra=2) + +Using initial data with a formset +--------------------------------- + +Initial data is what drives the main usability of a formset. As shown above +you can define the number of extra forms. What this means is that you are +telling the formset how many additional forms to show in addition to the +number of forms it generates from the initial data. Lets take a look at an +example:: + + >>> ArticleFormSet = formset_factory(ArticleForm, extra=2) + >>> formset = ArticleFormSet(initial=[ + ... {'title': u'Django is now open source', + ... 'pub_date': datetime.date.today()}, + ... ]) + + >>> for form in formset.forms: + ... print form.as_table() + <tr><th><label for="id_form-0-title">Title:</label></th><td><input type="text" name="form-0-title" value="Django is now open source" id="id_form-0-title" /></td></tr> + <tr><th><label for="id_form-0-pub_date">Pub date:</label></th><td><input type="text" name="form-0-pub_date" value="2008-05-12" id="id_form-0-pub_date" /></td></tr> + <tr><th><label for="id_form-1-title">Title:</label></th><td><input type="text" name="form-1-title" id="id_form-1-title" /></td></tr> + <tr><th><label for="id_form-1-pub_date">Pub date:</label></th><td><input type="text" name="form-1-pub_date" id="id_form-1-pub_date" /></td></tr> + <tr><th><label for="id_form-2-title">Title:</label></th><td><input type="text" name="form-2-title" id="id_form-2-title" /></td></tr> + <tr><th><label for="id_form-2-pub_date">Pub date:</label></th><td><input type="text" name="form-2-pub_date" id="id_form-2-pub_date" /></td></tr> + +There are now a total of three forms showing above. One for the initial data +that was passed in and two extra forms. Also note that we are passing in a +list of dictionaries as the initial data. + +Formset validation +------------------ + +Validation with a formset is about identical to a regular ``Form``. There is +an ``is_valid`` method on the formset to provide a convenient way to validate +each form in the formset:: + + >>> ArticleFormSet = formset_factory(ArticleForm) + >>> formset = ArticleFormSet({}) + >>> formset.is_valid() + True + +We passed in no data to the formset which is resulting in a valid form. The +formset is smart enough to ignore extra forms that were not changed. If we +attempt to provide an article, but fail to do so:: + + >>> data = { + ... 'form-TOTAL_FORMS': u'1', + ... 'form-INITIAL_FORMS': u'1', + ... 'form-0-title': u'Test', + ... 'form-0-pub_date': u'', + ... } + >>> formset = ArticleFormSet(data) + >>> formset.is_valid() + False + >>> formset.errors + [{'pub_date': [u'This field is required.']}] + +As we can see the formset properly performed validation and gave us the +expected errors. + +Understanding the ManagementForm +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +You may have noticed the additional data that was required in the formset's +data above. This data is coming from the ``ManagementForm``. This form is +dealt with internally to the formset. If you don't use it, it will result in +an exception:: + + >>> data = { + ... 'form-0-title': u'Test', + ... 'form-0-pub_date': u'', + ... } + >>> formset = ArticleFormSet(data) + Traceback (most recent call last): + ... + django.newforms.util.ValidationError: [u'ManagementForm data is missing or has been tampered with'] + +It is used to keep track of how many form instances are being displayed. If +you are adding new forms via javascript, you should increment the count fields +in this form as well. + +Custom formset validation +~~~~~~~~~~~~~~~~~~~~~~~~~ + +A formset has a ``clean`` method similar to the one on a ``Form`` class. This +is where you define your own validation that deals at the formset level:: + + >>> from django.newforms.formsets import BaseFormSet + + >>> class BaseArticleFormSet(BaseFormSet): + ... def clean(self): + ... raise forms.ValidationError, u'An error occured.' + + >>> ArticleFormSet = formset_factory(ArticleForm, formset=BaseArticleFormSet) + >>> formset = ArticleFormSet({}) + >>> formset.is_valid() + False + >>> formset.non_form_errors() + [u'An error occured.'] + +The formset ``clean`` method is called after all the ``Form.clean`` methods +have been called. The errors will be found using the ``non_form_errors()`` +method on the formset. + +Dealing with ordering and deletion of forms +------------------------------------------- + +Common use cases with a formset is dealing with ordering and deletion of the +form instances. This has been dealt with for you. The ``formset_factory`` +provides two optional parameters ``can_order`` and ``can_delete`` that will do +the extra work of adding the extra fields and providing simpler ways of +getting to that data. + +``can_order`` +~~~~~~~~~~~~~ + +Default: ``False`` + +Lets create a formset with the ability to order:: + + >>> ArticleFormSet = formset_factory(ArticleForm, can_order=True) + >>> formset = ArticleFormSet(initial=[ + ... {'title': u'Article #1', 'pub_date': datetime.date(2008, 5, 10)}, + ... {'title': u'Article #2', 'pub_date': datetime.date(2008, 5, 11)}, + ... ]) + >>> for form in formset.forms: + ... print form.as_table() + <tr><th><label for="id_form-0-title">Title:</label></th><td><input type="text" name="form-0-title" value="Article #1" id="id_form-0-title" /></td></tr> + <tr><th><label for="id_form-0-pub_date">Pub date:</label></th><td><input type="text" name="form-0-pub_date" value="2008-05-10" id="id_form-0-pub_date" /></td></tr> + <tr><th><label for="id_form-0-ORDER">Order:</label></th><td><input type="text" name="form-0-ORDER" value="1" id="id_form-0-ORDER" /></td></tr> + <tr><th><label for="id_form-1-title">Title:</label></th><td><input type="text" name="form-1-title" value="Article #2" id="id_form-1-title" /></td></tr> + <tr><th><label for="id_form-1-pub_date">Pub date:</label></th><td><input type="text" name="form-1-pub_date" value="2008-05-11" id="id_form-1-pub_date" /></td></tr> + <tr><th><label for="id_form-1-ORDER">Order:</label></th><td><input type="text" name="form-1-ORDER" value="2" id="id_form-1-ORDER" /></td></tr> + <tr><th><label for="id_form-2-title">Title:</label></th><td><input type="text" name="form-2-title" id="id_form-2-title" /></td></tr> + <tr><th><label for="id_form-2-pub_date">Pub date:</label></th><td><input type="text" name="form-2-pub_date" id="id_form-2-pub_date" /></td></tr> + <tr><th><label for="id_form-2-ORDER">Order:</label></th><td><input type="text" name="form-2-ORDER" id="id_form-2-ORDER" /></td></tr> + +This adds an additional field to each form. This new field is named ``ORDER`` +and is an ``forms.IntegerField``. For the forms that came from the initial +data it automatically assigned them a numeric value. Lets look at what will +happen when the user changes these values:: + + >>> data = { + ... 'form-TOTAL_FORMS': u'3', + ... 'form-INITIAL_FORMS': u'2', + ... 'form-0-title': u'Article #1', + ... 'form-0-pub_date': u'2008-05-10', + ... 'form-0-ORDER': u'2', + ... 'form-1-title': u'Article #2', + ... 'form-1-pub_date': u'2008-05-11', + ... 'form-1-ORDER': u'1', + ... 'form-2-title': u'Article #3', + ... 'form-2-pub_date': u'2008-05-01', + ... 'form-2-ORDER': u'0', + ... } + + >>> formset = ArticleFormSet(data, initial=[ + ... {'title': u'Article #1', 'pub_date': datetime.date(2008, 5, 10)}, + ... {'title': u'Article #2', 'pub_date': datetime.date(2008, 5, 11)}, + ... ]) + >>> formset.is_valid() + True + >>> for form in formset.ordered_forms: + ... print form.cleaned_data + {'pub_date': datetime.date(2008, 5, 1), 'ORDER': 0, 'title': u'Article #3'} + {'pub_date': datetime.date(2008, 5, 11), 'ORDER': 1, 'title': u'Article #2'} + {'pub_date': datetime.date(2008, 5, 10), 'ORDER': 2, 'title': u'Article #1'} + +``can_delete`` +~~~~~~~~~~~~~~ + +Default: ``False`` + +Lets create a formset with the ability to delete:: + + >>> ArticleFormSet = formset_factory(ArticleForm, can_delete=True) + >>> formset = ArticleFormSet(initial=[ + ... {'title': u'Article #1', 'pub_date': datetime.date(2008, 5, 10)}, + ... {'title': u'Article #2', 'pub_date': datetime.date(2008, 5, 11)}, + ... ]) + >>> for form in formset.forms: + .... print form.as_table() + <input type="hidden" name="form-TOTAL_FORMS" value="3" id="id_form-TOTAL_FORMS" /><input type="hidden" name="form-INITIAL_FORMS" value="2" id="id_form-INITIAL_FORMS" /> + <tr><th><label for="id_form-0-title">Title:</label></th><td><input type="text" name="form-0-title" value="Article #1" id="id_form-0-title" /></td></tr> + <tr><th><label for="id_form-0-pub_date">Pub date:</label></th><td><input type="text" name="form-0-pub_date" value="2008-05-10" id="id_form-0-pub_date" /></td></tr> + <tr><th><label for="id_form-0-DELETE">Delete:</label></th><td><input type="checkbox" name="form-0-DELETE" id="id_form-0-DELETE" /></td></tr> + <tr><th><label for="id_form-1-title">Title:</label></th><td><input type="text" name="form-1-title" value="Article #2" id="id_form-1-title" /></td></tr> + <tr><th><label for="id_form-1-pub_date">Pub date:</label></th><td><input type="text" name="form-1-pub_date" value="2008-05-11" id="id_form-1-pub_date" /></td></tr> + <tr><th><label for="id_form-1-DELETE">Delete:</label></th><td><input type="checkbox" name="form-1-DELETE" id="id_form-1-DELETE" /></td></tr> + <tr><th><label for="id_form-2-title">Title:</label></th><td><input type="text" name="form-2-title" id="id_form-2-title" /></td></tr> + <tr><th><label for="id_form-2-pub_date">Pub date:</label></th><td><input type="text" name="form-2-pub_date" id="id_form-2-pub_date" /></td></tr> + <tr><th><label for="id_form-2-DELETE">Delete:</label></th><td><input type="checkbox" name="form-2-DELETE" id="id_form-2-DELETE" /></td></tr> + +Similar to ``can_order`` this adds a new field to each form named ``DELETE`` +and is a ``forms.BooleanField``. When data comes through marking any of the +delete fields you can access them with ``deleted_forms``:: + + >>> data = { + ... 'form-TOTAL_FORMS': u'3', + ... 'form-INITIAL_FORMS': u'2', + ... 'form-0-title': u'Article #1', + ... 'form-0-pub_date': u'2008-05-10', + ... 'form-0-DELETE': u'on', + ... 'form-1-title': u'Article #2', + ... 'form-1-pub_date': u'2008-05-11', + ... 'form-1-DELETE': u'', + ... 'form-2-title': u'', + ... 'form-2-pub_date': u'', + ... 'form-2-DELETE': u'', + ... } + + >>> formset = ArticleFormSet(data, initial=[ + ... {'title': u'Article #1', 'pub_date': datetime.date(2008, 5, 10)}, + ... {'title': u'Article #2', 'pub_date': datetime.date(2008, 5, 11)}, + ... ]) + >>> [form.cleaned_data for form in formset.deleted_forms] + [{'DELETE': True, 'pub_date': datetime.date(2008, 5, 10), 'title': u'Article #1'}] + +Adding additional fields to a formset +------------------------------------- + +If you need to add additional fields to the formset this can be easily +accomplished. The formset base class provides an ``add_fields`` method. You +can simply override this method to add your own fields or even redefine the +default fields/attributes of the order and deletion fields:: + + >>> class BaseArticleFormSet(BaseFormSet): + ... def add_fields(self, form, index): + ... super(BaseArticleFormSet, self).add_fields(form, index) + ... form.fields["my_field"] = forms.CharField() + + >>> ArticleFormSet = formset_factory(ArticleForm, formset=BaseArticleFormSet) + >>> formset = ArticleFormSet() + >>> for form in formset.forms: + ... print form.as_table() + <tr><th><label for="id_form-0-title">Title:</label></th><td><input type="text" name="form-0-title" id="id_form-0-title" /></td></tr> + <tr><th><label for="id_form-0-pub_date">Pub date:</label></th><td><input type="text" name="form-0-pub_date" id="id_form-0-pub_date" /></td></tr> + <tr><th><label for="id_form-0-my_field">My field:</label></th><td><input type="text" name="form-0-my_field" id="id_form-0-my_field" /></td></tr> + +Using a formsets in views and templates +--------------------------------------- + +Using a formset inside a view is as easy as using a regular ``Form`` class. +The only thing you will want to be aware of is making sure to use the +management form inside the template. Lets look at a sample view:: + + def manage_articles(request): + ArticleFormSet = formset_factory(ArticleForm) + if request.method == 'POST': + formset = ArticleFormSet(request.POST, request.FILES) + if formset.is_valid(): + # do something with the formset.cleaned_data + else: + formset = ArticleFormSet() + return render_to_response('manage_articles.html', {'formset': formset}) + +The ``manage_articles.html`` template might look like this:: + + <form method="POST" action=""> + {{ formset.management_form }} + <table> + {% for form in formset.forms %} + {{ form }} + {% endfor %} + </table> + </form> + +However the above can be slightly shortcutted and let the formset itself deal +with the management form:: + + <form method="POST" action=""> + <table> + {{ formset }} + </table> + </form> + +The above ends up calling the ``as_table`` method on the formset class. + More coming soon ================ |