我正在尝试构建一个食谱应用程序，允许用户上传图像并将食谱保存在列表中。我面临的问题是，当用户不上传图像时，我会收到错误：attribute has no file associated with it.
错误
我看过Django的文档&尝试在我的HTML模板中使用default标记，但没有成功。该值在models.py 中命名为image_ingredients
我如何才能让用户将ImageField留空？
这是我的代码：
型号.py
# Recipe Field
class Recipe(models.Model):
title = models.CharField(max_length=200)
# TODO: Add default image if image is left blank
image = models.ImageField(upload_to='recipes/images/', blank=True)
category = models.ForeignKey(Category, on_delete=models.CASCADE,)
daily_meals = ['Breakfast', 'Brunch', 'Elevenses', 'Lunch', 'Tea', 'Supper', 'Dinner']
meal = models.ForeignKey(Meal, limit_choices_to={'name__in': daily_meals}, on_delete=models.CASCADE,)
image_ingredients = models.ImageField(upload_to='recipes/images/', null=True, blank=True)
ingredients = models.TextField(blank=True)
user = models.ForeignKey(User, on_delete=models.CASCADE)
def __str__(self):
return self.title
视图.py
# Solo recipe with instructions
def solo(request, recipe_id):
recipe = get_object_or_404(Recipe, pk=recipe_id)
return render(request, 'recipes/solo.html', {'recipe':recipe})
solo.html
<h4>Ingredients</h4>
<img src="{{ recipe.image_ingredients.url }}">
<p>{{ recipe.ingredients }}</p>
只有当存在image_ingredients项目时，才能渲染图像，例如：
<h4>Ingredients</h4>
{% if recipe.image_ingredients %}<img src="{{ recipe.image_ingredients.url }}">{% endif %}
<p>{{ recipe.ingredients }}</p>