如何使用自定义django templatetag与django模板if语句？ [英] how to use custom django templatetag with django template if statement?

问题描述

我已经制作了一个django模板标签，可以计算我的一个自定义用户多对多字段长度：

 从django导入模板
 
 register = template.Library（）
 
 @ register.simple_tag（took_context = True）
 def unread_messages_count（context）：
 user = context ['request']。user 
 return len（user.messages_unread.all（））
  

并且在模板本身中，只有当它大于零时才想将其显示给用户，所以我尝试：

  {％ifnotequal unread_messages_count 0％} 
一些代码... 
 {％endifnotequal％} 
  

但显然它没有工作。甚至没有'with'语句：

  {％with unread_messages_count as unread_count％} 
 {％ifnotequal unread_count 0 ％} 
一些代码... 
 {％endifnotequal％} 
 {％endwith％} 
  

如何检查变量是否大于0，只有当它是，给用户一些代码（包括变量本身的数字）。
谢谢。

解决方案

最简单的方法是使用赋值标签..

https：// docs.djangoproject.com/en/dev/howto/custom-template-tags/#assignment-tags

  @ register.assignment_tag（took_context = True）
 def unread_messages_count（context）：
 user = context ['request']。user 
 return len（user.messages_unread.all（））
 
 {％unread_messages_count as cnt％} 
 {％if cnt％} 
 foo 
 {％endif％} 
  pre> 
I've made a django template tag that counts one of my custom user many-to-many field length:
from django import template

register = template.Library()

@register.simple_tag(takes_context=True)
def unread_messages_count(context):
    user = context['request'].user
    return len(user.messages_unread.all())
and within the template itself, I want to show it to user only if it's larger than zero, so I tried:
{% ifnotequal unread_messages_count 0 %}
   some code...
{% endifnotequal %}
but obviously it didn't work. not even with a 'with' statement:
{% with unread_messages_count as unread_count %}
    {% ifnotequal unread_count 0 %}
        some code...
    {% endifnotequal %}
{% endwith %}
How can I check that the variable is larger than 0 and only if it is, present some code to the user (including the number in the variable itself).
thanks.
解决方案
The easiest way would be to use an assignment tag..

https://docs.djangoproject.com/en/dev/howto/custom-template-tags/#assignment-tags
@register.assignment_tag(takes_context=True)
def unread_messages_count(context):
    user = context['request'].user
    return len(user.messages_unread.all())

{% unread_messages_count as cnt %}
{% if cnt %}
   foo
{% endif %}


                        
这篇关于如何使用自定义django templatetag与django模板if语句？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！