How to perform conditional judgments (if/elif/else) in Anqi CMS template?

As an experienced CMS website operation personnel, I know that the flexibility of templates is crucial for efficient operation in daily content management.Especially conditional judgments, which allow us to intelligently control the display and hiding of content based on different data states and business logic, thus providing users with more accurate and personalized browsing experiences.The Anqi CMS template engine borrows the syntax style of Django, making the implementation of conditional judgments both powerful and easy to understand.

Basic structure of conditional judgment in Anqi CMS template

In Anqi CMS template, conditional judgment is mainly realized throughif/elif(short for else if) andelsetags and implemented byendifThe tag ends. This structure is very similar to conditional statements in many programming languages, making it easy for operations personnel familiar with programming logic to quickly get started.

The structure of a basic conditional judgment statement is as follows:

{% if 条件 %}
    <!-- 当条件为真时显示的内容 -->
{% endif %}

If you need to handle multiple cases, you can introduceelifandelse:

{% if 条件1 %}
    <!-- 当条件1为真时显示的内容 -->
{% elif 条件2 %}
    <!-- 当条件1为假且条件2为真时显示的内容 -->
{% else %}
    <!-- 当所有条件都为假时显示的内容 -->
{% endif %}

AllifAll statements must end with{% endif %}tags must be correctly closed.

elements that make up the conditional expression

The core of conditional judgment lies in the construction of its expressions. Anqi CMS template supports various types of expressions, helping us precisely define judgment logic.

FirstlyComparison operatorWe can use common comparison operators to determine the relationship of values:

• Equal:==(For example)archive.Id == 10)
• Not equal:!=(For example)item.Id != 1)
• Greater than:>(For example)simple.number > 42)
• Less than:<(For example)simple.number < 42)
• Greater than or equal to:>=(For example)simple.number >= 42)
• Less than or equal to:<=(For example)simple.number <= 42)

Next isLogical operatorThey allow us to combine multiple conditions to form more complex judgments:

• Logical AND:&&orand(For example)true && (true && (1 == 1 || false)))
• Logical OR:||oror(For example)true || false)
• Logical NOT:!ornot(For example)!true,not complex.post)

Additionally, there aremember operator inUsed to check if a value exists in a collection (such as an array, map):

• For example5 in simple.intmapIt will judge5whether it existssimple.intmapin this collection.

The Anqi CMS template also handles certain values:Implicit true and false judgmentFor example, non-empty strings, non-zero numbers, non-empty lists or objects are usually consideredtrue; while empty strings, zero,nil(empty values) or empty lists are consideredfalseThis means we can directly go through{% if 变量名 %}to determine whether a variable has a value or is true.

The actual application of conditional judgment in templates

Conditional judgments are widely used in daily website operations, and the following are some common examples:

Content display or hide according to data status:We can decide whether to display relevant information based on the review status of the content, whether there are subcategories, or a specific attribute. For example, in the comment list, we can determine whether a comment is being reviewed:

{% if item.Status != 1 %}
    <span>此评论正在审核中</span>
{% else %}
    <span>{{item.Content}}</span>
{% endif %}

Or determine if a category has subcategories to decide whether to display the subcategory list or the document list under the category:

{% if item.HasChildren %}
    {% categoryList subCategories with parentId=item.Id %}
        <!-- 显示子分类 -->
    {% endcategoryList %}
{% else %}
    {% archiveList products with type="list" categoryId=item.Id limit="8" %}
        <!-- 显示该分类下的产品 -->
    {% endarchiveList %}

Handle special items in the list:When traversing a list in a loop, we often need to handle the first, last, or items that meet specific conditions differently. Byforloop.Counter(the current loop index, starting from 1) andforloop.Revcounter(Remaining loop count) and loop variables can be easily implemented:

{% for item in archives %}
    <li class="{% if forloop.Counter == 1 %}active{% endif %}">
        <a href="{{item.Link}}">{{item.Title}}</a>
        {% if forloop.Counter == 1 %}
            <span>这是列表的第一项！</span>
        {% endif %}
    </li>
{% empty %}
    <li>没有内容</li>
{% endfor %}

Handle optional data and placeholders:Most of the time, images, descriptions, or other fields may not be present for all content. Using conditional judgment can prevent the appearance of empty spaces or incorrect links:

{% if item.Thumb %}
    <img src="{{item.Thumb}}" alt="{{item.Title}}">
{% else %}
    <img src="/static/images/default-thumb.png" alt="默认缩略图">
{% endif %}

Again, in SEO optimization, the canonical link (Canonical URL) may only exist on specific pages:

{%- tdk canonical with name="CanonicalUrl" %}
{%- if canonical %}
    <link rel="canonical" href="{{canonical}}" />
{%- endif %}

Make a conditional judgment based on a custom field:If the content model defines custom fields, we can also judge based on the values of these fields. For example, a boolean custom field namedis_featuredis:

{% archiveDetail archive with name="is_featured" %}
{% if archive.is_featured %}
    <span class="featured-badge">推荐</span>
{% endif %}

Or in the loop output custom fields while excluding some fields:

{% categoryDetail extras with name="Extra" %}
{% for field in extras %}
    {% if field.Name != 'author' and field.Name != 'price' %}
        <div>{{field.Name}}：{{field.Value}}</div>
    {% endif %}
{% endfor %}

Nested and combined use

The conditional judgment statement in Anqi CMS template can be nested at any level and can be used with other template tags such asforCombining loops seamlessly. This powerful combination allows us to organize complex page logic in a highly structured way.For example, in a navigation list, determine if there is a sub-navigation, and further determine whether a product list needs to be displayed in the sub-navigation:

{% navList navList %}
    {%- for item in navList %}
        <li>
            <a href="{{ item.Link }}">{{item.Title}}</a>
            {%- if item.NavList %}
                <ul class="sub-menu">
                    {%- for inner in item.NavList %}
                        <li>
                            <a href="{{ inner.Link }}">{{inner.Title}}</a>
                            {% archiveList products with type="list" categoryId=inner.PageId limit="8" %}
                                {% if products %}
                                    <ul class="product-list">
                                        {% for product in products %}
                                            <li><a href="{{product.Link}}">{{product.Title}}</a></li>
                                        {% endfor %}
                                    </ul>
                                {% endif %}
                            {% endarchiveList %}
                        </li>
                    {% endfor %}
                </ul>
            {% endif %}
        </li>
    {% endfor %}
{% endnavList %}

This example shows how to nest in a loopforwithin a loopifDetermine andifAnother one nested inside the judgeforloop andifDetermine to achieve complex navigation structures.

Details and precautions

• Tag closure:Make sure each{% if %}is matched with{% endif %}Otherwise, the template will not be parsed correctly.
• Case Sensitive:Labels, variable names, and parameters in the template