Django模板中如何根据枚举值控制元素的显示与隐藏？

方法一：将枚举类传入模板上下文 #

在视图函数里把DeviceState枚举类添加到模板上下文，就能在模板中直接引用枚举成员做判断：

1. 视图函数中补充上下文：

from django.shortcuts import render
from .your_module import DeviceState, Light

def your_view(request):
    lights = [Light(1, "客厅灯", DeviceState.ON), Light(2, "卧室灯", DeviceState.OFF)]
    # 将枚举类传入模板
    return render(request, 'your_template.html', {'lights': lights, 'DeviceState': DeviceState})

2. 模板中直接使用枚举成员判断：

{% for light in lights %}
    <tr>
        <td>{{ light.name }}</td>
        <td>{{ light.state }}</td>
        <td>
            {% if light.state == DeviceState.ON %}
                <button type="button" class="btn btn-dark">Lights off</button>
            {% endif %}
            {% if light.state == DeviceState.OFF %}
                <button type="button" class="btn btn-success">Lights on</button>
            {% endif %}
        </td>
    </tr>
{% endfor %}

方法二：直接判断枚举的value或name属性 #

light.state是枚举实例对象，你可以访问它的value（对应枚举定义的数值）或name（对应枚举的名称字符串）属性来做判断：

判断数值value： #

{% if light.state.value == 3 %}
    <button type="button" class="btn btn-dark">Lights off</button>
{% endif %}
{% if light.state.value == 4 %}
    <button type="button" class="btn btn-success">Lights on</button>
{% endif %}

判断名称name： #

{% if light.state.name == "ON" %}
    <button type="button" class="btn btn-dark">Lights off</button>
{% endif %}
{% if light.state.name == "OFF" %}
    <button type="button" class="btn btn-success">Lights on</button>
{% endif %}

方法三：在Light类中添加辅助方法 #

给Light类添加判断状态的方法，让模板调用更直观：

class Light:
    def __init__(self, id, name, state: DeviceState = DeviceState.UNKNOWN):
        self.id = id
        self.name = name
        self.state: DeviceState = state

    def is_on(self):
        return self.state == DeviceState.ON

    def is_off(self):
        return self.state == DeviceState.OFF

模板中调用方法判断：

{% for light in lights %}
    <tr>
        <td>{{ light.name }}</td>
        <td>{{ light.state }}</td>
        <td>
            {% if light.is_on %}
                <button type="button" class="btn btn-dark">Lights off</button>
            {% endif %}
            {% if light.is_off %}
                <button type="button" class="btn btn-success">Lights on</button>
            {% endif %}
        </td>
    </tr>
{% endfor %}

原写法失效的原因 #

你之前尝试的== 3、== "OFF"等写法无效，是因为light.state是DeviceState枚举的实例对象，不是单纯的数字或字符串。直接和数字、字符串比较时，类型不匹配，判断结果永远为False。

内容的提问来源于stack exchange，提问作者Sven van den Boogaart