# Using the Helper classes

Helper classes enable you to generate standard HTML elements for the back office as well as for module configuration pages.

PrestaShop 1.5 introduced 5 Helper classes, along with the `Helper` parent class: `HelperForm`, `HelperOptions`, `HelperList`, `HelperView`, and `HelperHelpAccess`. Among these, only the first three will be useful to developer, the last two being more internal helpers for the first three.

PrestaShop 1.6 adds a handful more: `HelperCalendar`, `HelperUploader`, `HelperImageUploader`, `HelperKpi`, `HelperKpiRow`, `HelperTreeCategories`, and `HelperTreeShops`. Again of these have no direct use developers: their features are directly handled by the main Helpers.\
For instance, the new uploading system, handled by `HelperUpload` (and `HelperImageUploader` for product images), is directly used by `HelperForm` when generating a `<input type="file">` element.

Therefore, you will most of the time only deal with `HelperForm`.

## The Main Helpers <a href="#usingthehelperclasses-themainhelpers" id="usingthehelperclasses-themainhelpers"></a>

All the helper classes inherit from the `Helper` parent class:

* [HelperForm](/1-6-documentation/english-documentation/developer-guide/developer-tutorials/using-the-helper-classes/using-the-helperform-class.md): used to generate an edition form for an object of type `ObjectModel`. Example: editing the client's profile.
* [HelperOptions](/1-6-documentation/english-documentation/developer-guide/developer-tutorials/using-the-helper-classes/using-the-helperoptions-class.md): used to generate a configuration form, the values of which are stored in the `configuration` table. Example: the "Preferences" page.
* [HelperList](/1-6-documentation/english-documentation/developer-guide/developer-tutorials/using-the-helper-classes/using-the-helperlist-class.md): used to generate a table of elements. The elements can belong to `ObjectModel`-type objects, but they do not have to. Example: client list, order status list, etc.

## The Helper Templates <a href="#usingthehelperclasses-thehelpertemplates" id="usingthehelperclasses-thehelpertemplates"></a>

The helpers use Smarty templates which are found in the following folder: `admin/themes/default/template/helpers/`**`name_of_the_helper`**`/`

Each template can be overloaded.

## Helper Overloading <a href="#usingthehelperclasses-helperoverloading" id="usingthehelperclasses-helperoverloading"></a>

An `AdminController` can overload any Helper template, simply by creating a `.tpl` file of the same name in the folder named `admin/themes/default/controllers/`**`name_of_the_controller`**`/helpers/`**`name_of_the_helper`**`/`

If possible, it should extend the parent template, not just replace it. Smarty 3 allows for inheritance by declaring `{block name=""}` tags. A child template can overload a parent block by opening a block of the same name.

In addition to this section, you can read how to [use helpers to overload a back office template](http://doc.prestashop.com/display/PS15/Using+helpers+to+overload+a+back-office+template).

### Template inheritance example: adding a new type of field in a form <a href="#usingthehelperclasses-templateinheritanceexample-addinganewtypeoffieldinaform" id="usingthehelperclasses-templateinheritanceexample-addinganewtypeoffieldinaform"></a>

For the sake of this example, let's change the edition for the client's addresses. We want a field that would display the name and e-mail of the client, if these are known, or an e-mail input field otherwise.

We must create a new template: `/admin-dev/themes/default/template/controllers/addresses/helpers/form/form.tpl`

This template will contain the following code:

```
{extends file="helpers/form/form.tpl"}
 
{block name="field"}
    {if $input.type == 'text_customer'}
        {if isset($customer)}
            ...
        {else}
            ...
        {/if}
    {else}
        {$smarty.block.parent}
    {/if}
{/block}
```

We first declare the template's parent, then we can overload its `field` block. That block contains the field display. Our code checks the field type:

* If it is of type `text_customer`, then it handles the content display.
* If it is of any other type, it gives way to the parent's handling code.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.prestashop-project.org/1-6-documentation/english-documentation/developer-guide/developer-tutorials/using-the-helper-classes.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.