def model_to_dict(instance, fields=None, exclude=None): """ Returns a dict containing the data in ``instance`` suitable for passing as a Form's ``initial`` keyword argument. ``fields`` is an optional list of field names. If provided, only the named fields will be included in the returned dict. ``exclude`` is an optional list of field names. If provided, the named fields will be excluded from the returned dict, even if they are listed in the ``fields`` argument. """ from django.db import models opts = instance._meta data = {} for f in chain(opts.concrete_fields, opts.private_fields, opts.many_to_many): if not getattr(f, 'editable', False): continue if fields and f.name not in fields: continue if exclude and f.name in exclude: continue data[f.name] = f.value_from_object(instance) # Evaluate ManyToManyField QuerySets to prevent subsequent model # alteration of that field from being reflected in the data. if isinstance(f, models.ManyToManyField): data[f.name] = list(data[f.name]) return data @total_ordering@python_2_unicode_compatibleclass Field(RegisterLookupMixin): # "省略其他代码..." def value_from_object(self, obj): """ Returns the value of this field in the given model instance. """ return getattr(obj, self.attname)上面是django中model_to_dict的源码,通过注释我们可以非常的明白这个方法的作用,然而在实体项目中,因为习惯了构造dict的方式作为返回值,所以大多数的时候我们也不太会想到它,以至于我都忘了他,然而却不能忽略拥有它的方便.
使用场景
- 在模型类字段很多且需要全部返回或大部分都需要返回的时候
- 只使用model中的几个字段值,而又不常用的modelview