Question

i have a modelform like so:

class CommentForm(forms.ModelForm):
    storyId = forms.IntegerField(required=True, widget=forms.HiddenInput())
    postId = forms.IntegerField(required=True, widget=forms.HiddenInput())

so now i want to change the value of the “storyId”

i’ve found that, in my code i need to do this:

form = CommentForm()
form.initial['storyId'] = xyz

or in the init of the model i need this:

self.initial['storyId'] = xyz

what is the “initial” doing? Why cannot i just go straight to:

form = CommentForm()
form.storyId = xyz

thanks!

UPDATE if i run form.storyId = xyz, then in the template, I will not see the value passed in. If i run

form.initial['storyId'] = xyz

then in the template i do see the values passed in! No other code changes, any ideas?

Answer 1

The parameter “initial” is used in forms.Form class generally to initialize a value that you would like to see as auto-filled, when the form is rendered.

In case of ModelForm, initial is used when you need to autofill a field that’s called from the forms’s init method.

form = CommentForm()
form.storyId = xyz

In the above code you are assigning directly the value to a property of a Python Instance, then the type of the property also changes.

The variable storyId is actually a django.forms.fields.IntegerField, and this has a parameter “initial” that would initialize the value.

Once you assign form.storyId=xyz, then storyId, takes the value of xyz, and will not be rendered as a form field.

I hope this is clear.