How do I make a field readonly or disabled so that it cannot be edited in Django form

Question

When the form is being used to create a new entry, all fields should be enabled - but when the record is in update mode some fields need to be read-only.

For example, when creating a new Item model, all fields must be editable, but while updating the record, is there a way to disable the sku field so that it is visible, but cannot be edited?

class Item(models.Model):
    sku = models.CharField(max_length=50)
    description = models.CharField(max_length=200)
    added_by = models.ForeignKey(User)


class ItemForm(ModelForm):
    class Meta:
        model = Item
        exclude = ('added_by')

def new_item_view(request):
    if request.method == 'POST':
        form = ItemForm(request.POST)
        # Validate and save
    else:
            form = ItemForm()
    # Render the view

Can class ItemForm be reused? What changes would be required in the ItemForm or Item model class? Would I need to write another class, "ItemUpdateForm", for updating the item?

def update_item_view(request):
    if request.method == 'POST':
        form = ItemUpdateForm(request.POST)
        # Validate and save
    else:
        form = ItemUpdateForm()

In a Django form, how do I make a field read-only (or disabled)?

Answer 1

Hello @kartik,

Setting readonly on a widget only makes the input in the browser read-only. Adding a clean_sku which returns instance.sku ensures the field value will not change on form level.

def clean_sku(self):
    if self.instance: 
        return self.instance.sku
    else: 
        return self.fields['sku']

This way you can use model's (unmodified save) and avoid getting the field required error.

Hope it helps!!

Thank you!!