如何确定Django模型形式中的字段是否已更改 [英] How to determine if a field has changed in a Django modelform

问题描述

我很惊讶这很难做到。但是我想到了这一点，这似乎至少对我的简单案例有用。有人可以推荐一种更好的方法吗？

I was surprised that this was difficult to do. However I came up with this, which seems to work at least for my simple case. Can anyone recommend a better approach?

def field_changed(self, fieldname):
    """Tests if the value of the field changed from the original data"""
    orig_value = self.fields[fieldname].initial or getattr(self.instance, field, None)
    orig_value = getattr(orig_value, 'pk', orig_value)
    if type(orig_value) is bool:
        # because None and False can be interchangeable
        return bool(self.data.get(fieldname)) != bool(orig_value)
    else:
        return unicode(self.data.get(fieldname)) != unicode(orig_value)

推荐答案

表单包含一个属性changed_data，该属性包含其值已更改的所有字段的列表。

Form contains a property changed_data which holds a list of all the fields whose values have changed.

尝试：

'fieldname' in myforminstance.changed_data

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