Flexible control of content display in the template creation of Anqi CMS is the key to improving user experience and meeting diverse business needs.As an experienced website operator, I am well aware of the importance of dynamic content presentation.The AnQi CMS adopts syntax similar to the Django template engine, which allows content operators to implement conditional judgments in templates in a straightforward manner, thereby precisely controlling which content is visible to users at what time and place.
The template syntax design of AnQi CMS makes it easy for developers and content operators to get started. Conditional judgments are made through{% if 条件 %}tags to enable, and need to be made through{% endif %}Label clearly ends.This structure allows us to embed logic in HTML templates and determine the rendering of page elements based on different data states.For example, we can choose different display styles based on whether the article has a thumbnail or based on the user's login status to show different navigation menus.
The most basic conditional judgment is to useifCheck if a certain condition is true. WhenifThe code block contained within the label is executed when the condition is evaluated to true.This is very useful in many scenarios.true.archive.Idequals10We can display a piece of content like this:{% if archive.Id == 10 %}这是文档ID为10的文档{% endif %}Similarly, to check if a variable namedsimpleis not empty ortrue,"{% if simple %}simple != nil{% endif %}.
When we need to handle multiple cases, the safe CMS template provideselseandelif(Short for else if) tag.elsetag is used toifWhen the condition is not met, an alternative execution path is provided.elifThen it allows us to add multiple additional conditions, evaluated in order, until the first true condition is found and its corresponding code block is executed.For example, on a category page, if the current category has a dedicated Banner image, we display the Banner image; if not, but there is a thumbnail, then we display the thumbnail; if neither is available, we display a default placeholder image.
{% categoryDetail bannerImages with name="Images" %}
{% categoryDetail thumbImage with name="Thumb" %}
{% if bannerImages %}
{# 如果存在Banner图，则显示第一张Banner图 #}
<img src="{{ bannerImages[0] }}" alt="分类Banner">
{% elif thumbImage %}
{# 如果没有Banner图但有缩略图，则显示缩略图 #}
<img src="{{ thumbImage }}" alt="分类缩略图">
{% else %}
{# 如果都没有，则显示默认占位图 #}
<img src="/static/images/default-category.png" alt="默认分类图">
{% endif %}
In conditional judgments, we can also use logical operators to construct more complex conditional expressions, including "and" (andor&&）、“or”oror||）and “not”（notor!）。Furthermore，“inandnot inThe operator can be used to check if a value exists in a list or set.For example, we can determine if a number is within a certain range, or if a string contains a certain substring.{% if simple.number < 42 || simple.number > 50 %}数字不在42到50之间{% else %}数字在42到50之间{% endif %}.
There are many common practice scenarios when using conditional judgment in templates. For example, when displaying a list of articles, it is usually necessary to checkitem.ThumbDoes it exist, to decide whether to display the thumbnail of the article:
{% archiveList archives with type="list" limit="10" %}
{% for item in archives %}
<li>
<a href="{{item.Link}}">
<h5>{{item.Title}}</h5>
</a>
{% if item.Thumb %}
{# 如果文章有缩略图，则显示它 #}
<a href="{{item.Link}}"><img alt="{{item.Title}}" src="{{item.Thumb}}"></a>
{% else %}
{# 否则显示一个默认的图片或不显示 #}
<span class="no-thumb-placeholder">暂无图片</span>
{% endif %}
</li>
{% endfor %}
{% endarchiveList %}
Another common scenario is to determine whether the current item in the loop is the first, last, or alternate style rendering based on loop count when traversing data. Although this involves more of the characteristics of loop tags.ifJudgment is still the core:
{% for item in archives %}
<li class="{% if forloop.Counter is divisibleby 2 %}even{% else %}odd{% endif %}">
{# ... 列表项内容 ... #}
</li>
{% endfor %}
When using conditional judgment, some **practices can help us write clearer, more maintainable code. First, be sure to use{% endif %}to close every{% if %}or{% elif %}The block should maintain the integrity of the label. Secondly, when multiple exclusive conditions exist, priority should be given to{% elif %}instead of nested{% if %}This can avoid code redundancy and improve readability. Finally, if there are unnecessary blank lines in the template, you can use{%-or-%}Remove the whitespace around logical tags to make the generated HTML cleaner.
By proficiently mastering the if-else logic judgment in the Anqi CMS template, content operators can more accurately control the presentation of website content, providing users with a more personalized and richer browsing experience, thereby enhancing the overall attractiveness and user retention rate of the website.
Common Questions and Answers (FAQ)
问：在安企CMS的模板中，if语句可以支持哪些类型的条件判断？Answer: Aqin CMSif语句支持多种条件判断。你可以使用比较运算符（如==等于，!=不等于，<less than,>greater than,<=less than or equal to,>=greater than or equal to) to compare the value of variables. It also supports logical operators (andor&&,oror||,notor!）to combine or negate conditions. Additionally, you can check if a variable exists or istrue（i.e., not empty, not zero), and useinornot inTo determine whether a value exists in a list or a string.
Question: Can Iif-elsenested anotherif-elsestatement inside a statement block?答：Yes, the template of AnQi CMS fully supportsif-elsenested statements. This means you can have one{% if %}/{% elif %}or{% else %}The code block should contain the complete conditional judgment logic. When nesting, please make sure that eachifstatement has its corresponding{% endif %}Labels, to maintain the correct and readable structure of the template. Good indentation habits will also greatly help you manage complex nested logic.
问：If my conditional judgment does not work as expected, how should I debug the template?答：When the condition judgment does not take effect, first check whether the variable names in the condition expression are correct, and confirm that these variables are available in the template context. You can do this by temporarily outputting the values of these variables directly in the template (for example{{ myVariable }}To verify them, check whether they contain the data you expect.Next, try to simplify complex condition expressions by breaking them down into smaller, independent conditions for testing, in order to pinpoint the specific location of the problem.{% if %}/{% elif %}/{% else %}and{% endif %}Is the pairing and syntax of the label correct, especially ensuring there are no omissions{% endif %}.