Question

I have a model with an optional file field

class MyModel(models.Model):
  name = models.CharField(max_length=50)
  sound = models.FileField(upload_to= audio/ , blank=True)

让我们拿出价值

>>> test = MyModel(name= machin )
>>> test.save()

我为什么会这样做?

>>> test.sound
<FieldFile: None>
>>> test.sound is None
False

我如何检查是否有一套档案?

Answer 1

if test.sound.name: 
     print "I have a sound file"
else:   
     print "no sound"

Also, FileField s boolean value will be False when there s no file: bool(test.sound) == False when test.sound.name is falsy.

Answer 2

http://stackoverflow.com/a/5213095/9785224 从另一个问题来看,你可以尝试:

class MyModel(models.Model):
  name = models.CharField(max_length=50)
  sound = models.FileField(upload_to= audio/ , blank=True)

def __nonzero__(self):
    return bool(self.sound)

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