dede field id是什么标签？

Of course! The dede_fieldid is a crucial concept in DedeCMS (织梦内容管理系统), especially for developers and advanced users who need to customize templates or extend the system's functionality.

Let's break it down in detail.

What is dede_fieldid?

In simple terms, dede_fieldid is a PHP variable used in DedeCMS templates to get the numerical ID of a specific custom field (also known as an extended field or additional field).

This ID corresponds to the id field in the dede_arctype table (for channel fields) or the dede_arcatt table (for article attributes).

Why is it Used? (The Purpose)

You might be thinking, "Why do I need the ID when I can just use the field name like {dede:field.name/}?" The main reasons for using fieldid are:

1. Conditional Logic: This is the most common use. You can check if a custom field exists or has a value before displaying it. This prevents empty or broken HTML from appearing on your page.
2. Dynamic Class/ID Assignment: You can use the field ID to apply different CSS classes or IDs to HTML elements based on which custom field is being used. This is useful for styling.
3. JavaScript Interactions: You can pass the field ID to a JavaScript function to perform specific actions when a user interacts with a field.
4. Advanced Template Customization: In complex template structures, you might need to reference fields by their internal ID for programmatic generation.

How to Use dede_fieldid in Templates

The syntax for using dede_fieldid is within a DedeCMS tag loop. The most common tag for this is {dede:field name='array' /}.

Example 1: Basic Usage

Let's say you have a custom field named author_wechat. You want to display it only if it has a value.

1. Find the Field ID: You would typically find this in the DedeCMS backend under "Content" -> "Model Management" -> "Content Model" -> "Channel Fields". The ID for author_wechat might be, for example, 8.

2. Use in Template: You would wrap the field's display logic inside an if statement that checks the fieldid.

   
   （图片来源网络，侵删）

   {dede:field name='array'}
       <!-- This block will loop through all the channel's custom fields -->
       {if @me['fieldid'] == 8 && @me['value'] != ''}
           <div class="author-contact">
               <span>Author WeChat: </span>
               {@me['value']}
           </div>
       {/if}
   {/dede:field}

   Explanation:

   • {dede:field name='array' /}: This special tag fetches all the custom fields for the current channel/article as an associative array. Each element in the array represents a field.
   • @me: Inside a DedeCMS loop, @me refers to the current element being processed (in this case, the current field's data array).
   • @me['fieldid']: This accesses the id of the current field.
   • @me['value']: This accesses the value of the current field.
   • {if @me['fieldid'] == 8 && @me['value'] != ''}: This checks if the current field's ID is 8 (our author_wechat field) AND that its value is not empty. If both are true, the code inside the {if} block is executed.

Example 2: Styling Based on Field ID

Imagine you have different types of call-to-action (CTA) buttons, each with a custom field (e.g., cta_type_1, cta_type_2). You want to style them differently.

{dede:field name='array'}
    {if @me['fieldid'] == 9} <!-- Assuming cta_type_1 has ID 9 -->
        <a href="{@me['value']}" class="btn btn-primary">
            Learn More
        </a>
    {elseif @me['fieldid'] == 10} <!-- Assuming cta_type_2 has ID 10 -->
        <a href="{@me['value']}" class="btn btn-secondary">
            Download Now
        </a>
    {/if}
{/dede:field}

Where to Find the Field ID

To use fieldid, you first need to know the ID of your custom field. Here's how to find it:

1. Log in to your DedeCMS backend.
2. Navigate to Content -> Model Management -> Content Model.
3. Click on the name of the content model you are using (e.g., "Article").
4. In the menu that appears, click on Channel Fields.
5. You will see a list of all your custom fields. The ID column shows the numerical ID for each field. You can also find the field names here.

Important Distinction: fieldid vs. typeid

It's crucial not to confuse dede_fieldid with typeid.

Summary

While using the field name directly (e.g., {dede:field.author_wechat/}) is simpler for direct display, dede_fieldid provides the flexibility needed for robust, dynamic, and professional template development in DedeCMS.