Exclude fields for Django model, only on creation - django

Question

I am building a notification system for a company, where admin users can create Projects and add users to them. The Project model has 9 attributes but I only want to show 3 or 4 fields when a Project is created, but show them all when an existing Project is updated.
This change will only need to be reflected on the Django admin site, so I have extended the ProjectAdmin with my own ProjectForm, where I extend the init method to check if it is a new instance and if so remove certain fields.
# models.py
class Project(models.Model):
project_number = models.IntegerField()
name = models.CharField(max_length=100)
permit = models.CharField(max_length=100, blank=True, default='')
is_active = models.BooleanField(default=True)
users = models.ManyToManyField(CustomUser, blank=True, related_name='project_users')
# add a default
levels = models.ManyToManyField('Level', blank=True, related_name='project_levels')
total_contract_hours = models.IntegerField(default=0, blank=True, verbose_name='Total Design Hours')
hours_used = models.IntegerField(default=0, blank=True, verbose_name='Total Design Hours Used')
notes = models.ManyToManyField('notes.ProjectNote', related_name='core_project_notes', blank=True)
history = HistoricalRecords()
def __str__(self):
ret_str = "{} {}".format(self.project_number, self.name)
if self.permit:
ret_str += " | Permit: {}".format(self.permit)
return ret_str
# admin.py
class ProjectForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(ProjectForm, self).__init__(*args, **kwargs)
attrs = {'class': 'form-control', 'required': True}
if self.instance and self.instance.pk is None:
# creating project
exclude = ['is_active', 'users', 'levels', 'hours_used', 'notes']
for field in exclude:
try:
del self.fields[field]
except ValueError:
print('{} does not exist'.format(field))
for field in self.fields.values():
field.widget.attrs = attrs
class Meta:
model = Project
fields = ['project_number', 'name', 'total_contract_hours']
class ProjectAdmin(admin.ModelAdmin):
form = ProjectForm
fields = ['project_number', 'name', 'permit', 'is_active', 'users', 'levels', 'total_contract_hours', 'hours_used', 'notes']
As I stated I only want basic Project fields on creation, but show all attributed when updating existing Project. With just these changes, I now get a KeyError:
KeyError: "Key 'is_active' not found in 'ProjectForm'. Choices are:
name, permit, project_number, total_contract_hours."
However, when I print the available fields it returns an OrderedDict with all of the model attributes as keys. What am I doing wrong? Thanks!

Answer 1

I figured it out, the field must be in listed in Meta and then you just set the field to be a hidden field.
class ProjectForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(ProjectForm, self).__init__(*args, **kwargs)
print("Adding project")
if not self.instance or self.instance.pk is None:
for name, field in self.fields.items():
if name in ['design_manager', ]:
field.widget = forms.HiddenInput()
class Meta:
model = Project
fields = ['project_number', 'name', 'design_manager', 'total_contract_hours']
class ProjectAdmin(admin.ModelAdmin):
form = ProjectForm
def save_model(self, request, obj, form, change):
obj.design_manager = request.user
super().save_model(request, obj, form, change)