I have a project in which I need to add a custom form field to a form (or formset) in which depending on the choice in the custom field selected, an integer in a database field is changed.
I can't seem to find any examples or prior questions which imply how to modify a database field via a custom field. I suspect it is done by overwriting the save() function in a ModelForm but cannot work out how.
Any advice on solving this problem would be greatly appreciated.
An Example:
My class has an integer field which is the field that needs updating.
class Employee(Model):
years = models.IntegerField()
However this field cannot be updated as it is, instead what is needed is a ChoiceField (I think) with different options that, depending on the selection, changes the field with a +1, -1, or reset to zero.
As previously mentioned this is where I imagine some work with the save() function needs to be done but am unsure.
As a side note in case this affects what can be done, eventually this ModelForm will need to be used in a formset so I can edit multiple objects on one page.
Related
I use "msignup" model for user signups. after signup is complete which works just fine, in the profile of the user I want to let them change some basic information that they used during the signup (which are saved in database in msignup model) using modelform named "accountSettingsForm".
Obviously the original user information must be there in the "accountSettingsForm " and the user would change any piece of information he/she likes.
I know it is possible to set the initial value of the accountSettingsForm:
form = accountSettingsForm(initial={'someFieldName':snomeVariable})
But I assume there is a better way of doing this that I don't know about.
Probably using __init__ methods is more appropriate.
Any helps will be greatly appreciated.
First of all I have tried to research my problem but have not been able to find what I need. My problem might be related to the design of my project (any help would be appreciated).
The problem I am facing is as follows:
I have a few models
I have a model that would be used specifically to create a ModelForm
In this model I have ForeignKey field that is represented by default as a select/option input widget in the ModelForm (for each the value attribute is the ForeignKey and text between the tags is the __str__() of the model the ForeignKey points to. The user sees the __str__() and value attribute of the option tag is submitted which is great).
So far so good but I want to replace the widget with an input text field so I can implement it as a search field.
Now when the user submits the form the string entered in the text input field is submitted and of course django doesn't like that since it expects a foreign key
I already can think of a few solutions to the problem and I am sure I can make it work but each of them feels like I would be violating some best practices. So my question is what should I do?
Do I exclude this particular field from the ModelForm and implement it as an input text field then after form submission make a query with it's value and then store the ForeignKey to the DB
Do I manipulate the data with JavaScript upon submission so that Django receives correct information
Can I clean this fields data with Django and transform it from string to FK?
Am I going the wrong way with this or there is a Django feature for this type of situation?
If anyone has the same problem here is the solution (to my problem at least):
I tried to use the clean_<fieldname> method to change the user entered string to database id. The method wasn't executing because the validation process was stopping earlier because of the difference between the form field and the widget. I redefined the form field to CharField so that step of the validation was working and then the clean_<fieldname> method executes without a problem.
I am programming an application in django, and I have a model where I defined some fields that are necessary to be filled. This way, when te user doesn't fill one of these fields, Django authomatically indicates to the user to fill it to create the specific object defined by the model.
But myquestion comes here: I want to reuse the same form to search objects defined by that model. And in this case, all the fields that before were necessary, now are OPTIONAL. But, as I have already defined the model so that the fields are necessary, django doesn´t let me define those fields as optional.
Is there any way to reuse that form where the fields are necessary, but making them OPTIONAL? Or I must create another different model or form in html? I know that creating another form manually in the html code the problem is solver, but I have curiosity to know if it can be reused.
Thank you so much!
You can programmatically change properties of a field within a form using its fields dictionary. So you could create a new form class that is derived from your current form class and in its __init__ set the required property of the fields you desired to be optional to be False like so:
self.fields['title'].required = False
I'm a newbie and right now I'm using Django forms to show some fields. One of these fields is a ModelChoiceField this show correctly model data, but I don´t know how I can fill a CharField later of select a option in the ModelChoiceField.
How I can make send the value of option selected for obtain the data that i need for later show this in a CharField, this is possible make directly from a djangoForm or do I need a new view to return the value?
There are two ways to achieve what you want I think:
Provide an initial value for your form value.
Bind your form to some data.
See this related stack overflow to provide initial values.
See Django's documentation on forms for binding data. There are two kinds of form states: bound and unbound. To create a bound form, you just need to create an instance of your form with some data: MyForm({'data-key1': 'data-value1', ...}).
I'm new to Django, and I haven't found the answer yet in the extensive documentation. I'm asking for pointers to research, not for working code. That being said, here's my problem:
In one of my models theres a BooleanField (it gets rendered in the admin form as a checkBox). Let's call it 'A'. It only makes sense to edit other field (say, CharField 'B') if A is checked.
So, is there a way to make B read only, or even changing its content to an empty string, dinamically, if A is checked? Thank you.
(Django 1.5.2, Python 2.7.5)
You're going to need several things to make this work. You may be able to skip some of them depending if you mainly care abut the UI, or the data integrity in the db.
Since the user can (presumably) check/uncheck Field A on the client-side you need some Javascript to enable/disable the appearance of Field B. These docs show how to load custom JS in your ModelAdmin class:
https://docs.djangoproject.com/en/dev/ref/contrib/admin/#modeladmin-asset-definitions
In your ModelForm you may want to do some check in the __init__ method against the value of self.instance.field_a and substitute some kind of ReadOnlyWidget for Field B for the initial display of the form. These docs show how to give your ModelAdmin a custom form class:
https://docs.djangoproject.com/en/dev/ref/contrib/admin/#django.contrib.admin.ModelAdmin.form
If you are writing some Javascript to do that dynamically it make be easier to skip this step and just do it client-side.
Finally you can use Django model validation to ensure that Field B is saved with a null value if Field A is checked:
https://docs.djangoproject.com/en/dev/ref/models/instances/#validating-objects