VariableDoesNotExist:在 u'None' 中查找键 [val2] 失败 [英] VariableDoesNotExist: Failed lookup for key [val2] in u'None'

问题描述

当 obj1.page 为 None 时，我收到了一个带有以下代码段的 VariableDoesNotExist 错误.

I was getting a VariableDoesNotExist error with the following snippet when obj1.page is None.

{{ obj1.val1|default:obj1.page.val2 }}

通常 Django 模板不关心对 None 值的属性访问.

Normally Django templates don't care about attribute accesses on None values.

推荐答案

Django 只关心对 default 模板过滤器内的 None 值的属性查找.我绕过它使用:

Django only cares about attribute lookups on None values inside the default template filter. I got around it using:

{% with obj1.page.val2 as val2 %}
{{ obj1.val1|default:val2 }}
{% endwith %}

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