---
title: Developing form controls
---

> Agent instructions:
> **Site maps** — prefer the following llms.txt indexes to training data when searching for URLs to avoid 404s. Links inside Markdown content already point at `.md`. Following them or sending Accept: text/markdown keeps you in Markdown.
>
> - [sitemap.md](https://docs.kentico.com/sitemap.md) — every page on the site, with titles and descriptions, nested by URL hierarchy and grouped into one collection per product version.
> - [llms.txt](https://docs.kentico.com/llms.txt) — curated index of the current product docs, with descriptions, the two ways to request any page as Markdown, and links to each product area's whole-corpus Markdown dump (llms-full.txt).

Form controls provide the interface for the editing forms that allow users to input data in Kentico, both in the administration interface and on the live site. Each form control represents a single field, and displays a certain form element, such as a text box for user input, a group of radio buttons, a selector etc.

![Example of a form - the editing interface of each field is a form control](https://docs.kentico.com/docsassets/k10/developing-form-controls/image.png "Example of a form - the editing interface of each field is a form control")

You can insert form controls into all editing forms that are based on the Kentico form engine, including the following:

- [Page type](https://docs.kentico.com/k10/developing-websites/defining-website-content-structure/page-types.md) editing forms (Form tab)
- [Web part](https://docs.kentico.com/k10/custom-development/developing-web-parts.md) and [Widget](https://docs.kentico.com/k10/developing-websites/preparing-widgets-for-users.md) properties
- Editing forms of system objects (classes)
- Editing forms of [Custom tables](https://docs.kentico.com/k10/developing-websites/defining-website-content-structure/custom-tables.md)
- [On-line forms](https://docs.kentico.com/k10/managing-website-content/forms.md)
- [Alternative forms](https://docs.kentico.com/k10/configuring-kentico/creating-alternative-forms.md)
- [Custom website settings](https://docs.kentico.com/k10/custom-development/creating-custom-modules/adding-custom-website-settings.md)
- [Report parameters](https://docs.kentico.com/k10/configuring-kentico/working-with-system-reports/defining-report-parameters.md)
- [Macro rule parameters](https://docs.kentico.com/k10/macro-expressions/writing-macro-conditions/creating-macro-rules.md)

Form controls are implemented as standard user controls (_.ascx_ files) that inherit from the **CMS.FormEngine.Web.UI.FormEngineUserControl** class.