I'm trying to make a form to edit the value of a ManyToMany field from its parent model. As an example, I have something similar to these three models:
class Language(models.Model):
label = models.CharField()
class Word(models.Model):
language = models.ForeignKey(Language)
word = models.CharField()
entries = models.ManyToManyField(Entries, null=True, blank=True)
class Entries(models.Model):
entry = models.CharField()
Each Language will have about 50 words. Each Word will have one or two entries each.
I'm generating the formset to edit the entries for a given language like this:
class WordForm(forms.ModelForm):
class Meta:
model = Word
hidden = ('language', )
PronounFormSet = inlineformset_factory(Language, Word,
can_delete=False, extra=0, form=WordForm)
This gives me a <select> which allows me to add/remove an Entry into Word.entries. However, I want to allow the user to edit the field Entries.entry directly (i.e. the field Entries.entry should be in a CharField(). How do I modify my WordForm to allow this?
I know there are probably better ways to do this (e.g. a different database schema), but I'm heavily constrained by a legacy implementation.
If you want the entry to be a text field, you can add a custom field to your ModelForm, and make sure the default field is not shown by explicitly identifying which fields should be shown:
class WordForm(forms.ModelForm):
class Meta:
model = Word
hidden = ('language', )
fields = ('word',)
entries = forms.CharField()
Your form validation logic should be like this:
for form in formset:
obj = form.save(commit=False)
obj.language = # select the language here
obj.save()
entry = Entries.objects.get_or_create(entry=form.cleaned_fields['entries'])
obj.entries.add(entry)
obj.save()
Keep in mind with this implementation, you can't edit fields using this form (since the character field will always be empty when the form is rendered).
Related
I have a (horrible) database table that will be imported from a huge spreadsheet. The data in the fields is for human consumption and is full of "special cases" so its all stored as text. Going forwards, I'd like to impose a bit of discipline on what users are allowed to put into some of the fields. It's easy enough with custom form validators in most cases.
However, there are a couple of fields for which the human interface ought to be a ChoiceField. Can I override the default form field type (CharField)? (To clarify, the model field is not and cannot be constrained by choices, because the historical data must be stored. I only want to constrain future additions to the table through the create view).
class HorribleTable( models.Model):
...
foo = models.CharField( max_length=16, blank=True, ... )
...
class AddHorribleTableEntryForm( models.Model)
class Meta:
model = HorribleTable
fields = '__all__' # or a list if it helps
FOO_CHOICES = (('square', 'Square'), ('rect', 'Rectangular'), ('circle', 'Circular') )
...?
Perhaps you could render the forms manually, passing the options through the context and make the fields in html.
Take a look at here:https://docs.djangoproject.com/en/4.0/topics/forms/#rendering-fields-manually
I think you can easily set your custom form field as long it will match the data type with the one set in your model (e.g. do not set choices longer than max_length of CharField etc.). Do the following where foo is the same name of the field in your model:
class AddHorribleTableEntryForm(forms.ModelForm):
foo = forms.ChoiceField(choices=FOO_CHOICES)
class Meta:
model = HorribleTable
...
I think this is perfectly fine for a creation form. It's will not work for updates as the values in the DB will most probably not match your choices. For that, I suggest adding a second form handling data updates (maybe with custom permission to restrict it).
UPDATE
Another approach will be to override the forms init method. That way you can handle both actions (create and update) within the same form. Let the user select from a choice field when creating an object. And display as a normal model field for existing objects:
class AddHorribleTableEntryForm(forms.ModelForm):
foo = forms.ChoiceField(choices=FOO_CHOICES)
class Meta:
model = HorribleTable
fields = '__all__' # or a list if it helps
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
instance = kwargs.get("instance", None)
if instance is None:
self.fields["foo"].widget = forms.widgets.Select(choices=self.FOO_CHOICES)
I have two models, Tag and TagGroup.
class TagGroup(models.Model):
tag_group_name = models.CharField(max_length=100)
class Tag(models.Model):
tag_name = models.CharField(max_length=100)
tag_group = models.ForeignKey(TagGroup, blank=True, null=True)
I've put a TagGroup form as a choice field into a template so that I can assign a TagGroup to a Tag. I created this form to populate from a TagGroup queryset.
class TagGroupForm(ModelForm):
tag_group_name = forms.ModelChoiceField(queryset=TagGroup.objects.values_list('id', 'tag_group_name'), required=False)
class Meta:
model = TagGroup
fields = [
'tag_group_name'
]
I haven't seen any obvious instructions how I can assign the Id to the Tag table while showing the user only the Tag value in the choice field in the template.
Currently the above shows:
Couple of questions:
is the queryset correct? I have tried without "values_list" but it then just shows an "Object" in the form field in template?
how do i 'hide' the Id so i can save on it, while only showing the user the actual string value in the form field?
Edited to add updated form:
class TagGroupForm(ModelForm):
tag_group_name = forms.ModelChoiceField(queryset=TagGroup.objects.all(), to_field_name = 'tag_group_name', required=False)
class Meta:
model = TagGroup
fields = [
'tag_group_name'
]
this now produces the following .. looks close .. the form value has a nice string but the actual value displayed to user is still "TagGroup object". How to get this to show?
From the docs,
The str (unicode on Python 2) method of the model will be called to generate string representations of the objects for use
So simply just assign this to the objects name and all will be ok! (Also, you don't need to use values_list) The reason it shows the Object by default is because this is what the default string representation is.
class TagGroup(models.Model):
tag_group_name = models.CharField(max_length=100)
def __str__(self):
return self.tag_group_name
tag_group_name = forms.ModelChoiceField(queryset=TagGroup.objects.all(), required=False)
Alternatively, if you don't wish to modify this and wish to reserve it for other uses.
To provide customized representations, subclass ModelChoiceField and override label_from_instance. This method will receive a model object, and should return a string suitable for representing it
class TagChoiceField(ModelChoiceField):
queryset = TagGroup.objects.all()
def label_from_instance(self, obj):
return obj.tag_group_name # or similar
I have a Django model with a ManyToManyField.
1) When adding a new instance of this model via admin view, I would like to not see the M2M field at all.
2) When editing an existing instance I would like to be able to select multiple options for the M2M field, but display only a subset of the M2M options, depending on another field in the model. Because of the dependence on another field's actual value, I can't just use formfield_for_manytomany
I can do both of the things using a custom ModelForm, but I can't reliably tell whether that form is being used to edit an existing model instance, or if it's being used to create a new instance. Even MyModel.objects.filter(pk=self.instance.pk).exists() in the custom ModelForm doesn't cut it. How can I accomplish this, or just tell whether the form is being displayed in an "add" or an "edit" context?
EDIT: my relevant code is as follows:
models.py
class LimitedClassForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(LimitedClassForm, self).__init__(*args, **kwargs)
if not self.instance._adding:
# Edit form
clas = self.instance
sheets_in_course = Sheet.objects.filter(course__pk=clas.course.pk)
self.Meta.exclude = ['course']
widget = self.fields['active_sheets'].widget
sheet_choices = []
for sheet in sheets_in_course:
sheet_choices.append((sheet.id, sheet.name))
widget.choices = sheet_choices
else:
# Add form
self.Meta.exclude = ['active_sheets']
class Meta:
exclude = []
admin.py
class ClassAdmin(admin.ModelAdmin):
formfield_overrides = {models.ManyToManyField: {
'widget': CheckboxSelectMultiple}, }
form = LimitedClassForm
admin.site.register(Class, ClassAdmin)
models.py
class Course(models.Model):
name = models.CharField(max_length=255)
class Sheet(models.Model):
name = models.CharField(max_length=255)
course = models.ForeignKey(Course)
file = models.FileField(upload_to=getSheetLocation)
class Class(models.model):
name = models.CharField(max_length=255)
course = models.ForeignKey(Course)
active_sheets = models.ManyToManyField(Sheet)
You can see that both Sheets and Classes have course fields. You shouldn't be able to put a sheet into active_sheets if the sheet's course doesn't match the class's course.
The following shows up instead of a field in my template.
<django.contrib.localflavor.us.forms.USStateSelect object at 0x92b136c>
my template has
{{ form.state }}
what could the issue be?
class RegistrationForm(forms.Form):
first_name = forms.CharField(max_length=20)
last_name = forms.CharField(max_length=20)
phone = USPhoneNumberField()
address1 = forms.CharField(max_length=45)
address2 = forms.CharField(max_length=45)
city = forms.CharField(max_length=50)
state = USStateSelect()
zip = USZipCodeField()
also is there anyway i can make the state and zip optional?
To limit the choices to a drop down list, use us.us_states.STATE_CHOICES in your model, and use us.forms.USStateField() instead of us.forms.USStateSelect() in your forms.
To make a field optional in a form, add blank = True to that field in the model.
from django.contrib.localflavor.us.us_states import STATE_CHOICES
from django.contrib.localflavor.us.models import USStateField
class ExampleLocation(models.Model):
address1 = models.CharField(max_length=45) #this is not optional in a form
address2 = models.CharField(max_length=45, blank = True) #this is made optional
state = USStateField(choices = STATE_CHOICES)
Instead of STATE_CHOICES, there are several options you can find in the localflavor documentation. STATE_CHOICES is the most inclusive, but that may not be what you desire. If you just want 50 states, plus DC, use US_STATES.
This answer assumes you're using ModelForms. If you aren't, you should be. Once you've made your model, you should follow DRY and create basic forms like so:
from django.forms import ModelForm
class ExampleForm(ModelForm):
class Meta:
model = ExampleLocation
And it inherits your fields from your model. You can customize what fields are available, if you don't want the whole model, with other class Meta options like fields or exclude. Model forms are just as customizable as any other form, they just start with the assumption of your model's fields.
I want to make a form used to filter searches without any field being required. For example given this code:
models.py:
class Message(models.Model):
happened = models.DateTimeField()
filename = models.CharField(max_length=512, blank=True, null=True)
message = models.TextField(blank=True, null=True)
dest = models.CharField(max_length=512, blank=True, null=True)
fromhost = models.ForeignKey(Hosts, related_name='to hosts', blank=True, null=True)
TYPE_CHOICES = ( (u'Info', u'Info'), (u'Error', u'Error'), (u'File', u'File'), (u'BPS', u'BPS'),)
type = models.CharField(max_length=7, choices=TYPE_CHOICES)
job = models.ForeignKey(Jobs)
views.py:
WHEN_CHOICES = ( (u'', ''), (1, u'Today'), (2, u'Two days'), (3, u'Three Days'), (7, u'Week'),(31, u'Month'),)
class MessageSearch(ModelForm): #Class that makes a form from a model that can be customized by placing info above the class Meta
message = forms.CharField(max_length=25, required=False)
job = forms.CharField(max_length=25, required=False)
happened = forms.CharField(max_length=14, widget=forms.Select(choices=WHEN_CHOICES), required=False)
class Meta:
model = Message
That's the code I have now. As you can see it makes a form based on a model. I redefined message in the form because I'm using an icontains filter so I didn't need a giant text box. I redefined the date mostly because I didn't want to have to mess around with dates (I hate working with dates! Who doesnt?) And I changed the jobs field because otherwise I was getting a drop down list of existing jobs and I really wanted to be able to search by common words. So I was able to mark all of those as not required
The problem is it's marking all my other fields as required because in the model they're not allowed to be blank.
Now in the model they can't be blank. If they're blank then the data is bad and I don't want it in the DB. However the form is only a filter form on a page to display the data. I'm never going to save from that form so I don't care if fields are blank or not. So is there an easy way to make all fields as required=false while still using the class Meta: model = Message format in the form? It's really handy that I can make a form directly from a model.
Also this is my first serious attempt at a django app so if something is absurdly wrong please be kind :)
You can create a custom ModelForm that suit your needs. This custom ModelForm will override the save method and set all fields to be non-required:
from django.forms import ModelForm
class SearchForm(ModelForm):
def __init__(self, *args, **kwargs):
super(SearchForm, self).__init__(*args, **kwargs)
for key, field in self.fields.iteritems():
self.fields[key].required = False
So you could declare your forms by simply calling instead of the ModelForm, e.g.:
class MessageForm(SearchForm):
class Meta:
model = Message
You could also pass empty_permitted=True when you instantiate the form, e.g.,
form = MessageSearch(empty_permitted=True)
that way you can still have normal validation rules for when someone does enter data into the form.
I would give a try to the django-filter module :
http://django-filter.readthedocs.io/en/develop/
fields are not required. these are filters actually. It would look like this :
import django_filters
class MessageSearch(django_filters.FilterSet):
class Meta:
model = Message
fields = ['happened', 'filename', 'message', '...', ]
# django-filter has its own default widgets corresponding to the field
# type of the model, but you can tweak and subclass in a django way :
happened = django_filters.DateFromToRangeFilter()
mandatory, hidden filters can be defined if you want to narrow a list of model depending on something like user rights etc.
also : setup a filter on a 'reverse' relationship (the foreignkey is not in the filtered model : the model is referenced elsewhere in another table), is easy, just name the table where the foreign key of the filtered model field is :
# the 'tags' model has a fk like message = models.ForeignKey(Message...)
tags= django_filters.<some filter>(name='tags')
quick extendable and clean to setup.
please note I didn't wrote this module, I'm just very happy with it :)