[Django]-Django, ModelChoiceField() and initial value

You can just use

 field1 = forms.ModelChoiceField(queryset=..., initial=0) 

to make the first value selected etc. It’s more generic way, then the other answer.

The times they have changed:

The default initial value can now be set by defining initial like other form fields except you set it to the id instead.

Now this will suffice:

form = YourForm(initial = {'field1': instance_of_mymodel })

Though both still work.

The code

form = YourForm(initial = {'field1': instance_of_mymodel.pk })

and

form = YourForm(initial = {'field1': instance_of_mymodel })

or initial field directly following:

field1 = forms.ModelChoiceField(queryset=..., initial=0) 

All work.

The first two ways will override the final way.

field1 = forms.ModelChoiceField(queryset=Model.objects.all(), empty_label="Selected value")

It’s as simple as that….!

Just want to add this answer after stumbling on this question. I know it works on Django 3.2, at least.
If you have some calculated value in the __init__ method, you can do this to set the initial value at instantiation as well:

def __init__(self, value, *args, **kwargs):
    # super call, etc.
    self.do_something(value)
    self.fields['field'].initial = value

If the form does multiple things with value, it’s a bit more DRY to pass it only once instead of redundantly with the initial kwarg in instantiation.

You could do this as well:

form = YourForm(initial = {'field1': pk })

if you are parsing your primary key through a query string or via an ajax call no need for an instance, the query set has already handled that for your drop down, the pk indexes the state you want