django中基于表单输入和字符串操作的查询

Django 表单中的字段 https://stackoverflow.com/questions/50841850/django-fields-in-form/50845891#50845891

正如问题 4 中所述，我需要获取表单输入并计算上传的每个图像的设计 ID。如何查询数据库以获取类别、面料、制造商和制造商位置的缩写，并将所有这些字符串连接起来以生成和存储设计 ID？

我已将此代码添加到我的views.py

image = form.save(commit=False)

cat = Category.objects.get(name=image['category'])      
fab = Fabric.objects.get(name=image['fabric'])
manu = Manufacturer.objects.get(name=image['manufacturer'])
setcat = Group.objects.get(name=image['set_cat'])
string = cat.abbr + "-" + fab.abbr + "-" + manu.name_abbr + "-" + manu.loc_abbr + "-" + image['selling_price'] + "-" + setcat.abbr + "-" + image['set_cat_no']
image['design_id'] = string

image.save()

这给了我错误 -“图像”对象没有属性“getitem'

我的图像模型models.py is this

class Images(models.Model):
    design_id = models.CharField(max_length=128)
    file = models.ImageField(upload_to='images')
    cost_price = models.FloatField()
    category = models.ForeignKey(Category, on_delete=models.CASCADE, blank=False)
    fabric = models.ForeignKey(Fabric, on_delete=models.CASCADE, blank=False)
    manufacturer = models.ForeignKey(Manufacturer, on_delete=models.CASCADE, blank=False)
    selling_price = models.FloatField()
    aliveness = models.IntegerField(default=1)
    date_added = models.DateTimeField(default=datetime.datetime.now)
    set_cat = models.ForeignKey(Group, on_delete=models.CASCADE, blank=False)
    set_cat_no = models.IntegerField()
    set_cat_name = models.CharField(max_length=50, blank=True)
    visit_count = models.IntegerField(default=0)

我尝试从返回 unicode()__unicode__但这也不起作用。

您不通过字典表示法访问模型实例属性。您需要使用点表示法，就像您在其他地方所做的那样。

image.design_id = string