--- title: Managing form controls related: - https://docs.kentico.com/k8/custom-development/developing-form-controls/defining-form-control-parameters.md - https://docs.kentico.com/k8/custom-development/developing-form-controls/example-developing-custom-form-controls.md - https://docs.kentico.com/k8/custom-development/developing-form-controls/reference-field-editor.md --- > 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). The **Form controls** application allows you to view the catalog of available form controls. Click **New form control** to register custom form controls. When you edit () a form control, the following properties are available on the **General** tab: | Display name | Sets the name of the form control used in the administration interface, for example when selecting form controls in the field editor. | | -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Code name | Serves as a unique identifier of the form control (for example in the API). | | Type | Assigns the form control to a category. The type can be used to filter form controls. | | File name | Contains the relative path to the _.ascx_ file that implements the form control.
Example: _\~/CMSFormControls/Basic/TextBoxControl.ascx_ | | Inherited from | Only available for [inherited form controls](https://docs.kentico.com/k8/custom-development/developing-form-controls/inheriting-from-existing-form-controls.md).
Displays the name of the parent form control. Replaces the **File name** (inherited controls use the same source file as their parent). | | Description | A text description of the control or comments for other administrators. | | High priority | When selecting a form control in the field editor, controls with high priority appear at the top of the list and are highlighted.
Additionally, only high priority form controls are included among the form controls offered in the [Form builder](https://docs.kentico.com/k8/managing-website-content/forms/designing-forms-using-the-form-builder.md).
Only enable this option for form controls that are most commonly used. | ### Control scope Use the properties in the **Use control for** section to choose the field types for which the form control is available. Possible attribute types for fields include standard data types (Text, Long text, Decimal, Integer, Long integer, Boolean, Date-time), as well as several other options: | Unique identifier (GUID) | Fields that store 32‑character strings used as globally unique identifiers for objects. | | ------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | File | Fields that provide file management. | | Document attachments | Fields that allow the management of document attachments. | | Visibility | For form controls that modify the visibility options of other fields.
See [Allowing users to change the information they share](https://docs.kentico.com/k8/managing-users/allowing-users-to-change-the-information-they-share.md) for more details. | The **Show control in** determines in which types of forms the control can be used: | Document types | Allows use in [document type](https://docs.kentico.com/k8/developing-websites/defining-website-data-structure/document-types.md) fields, which you can edit in **Document types -> edit document type -> Fields**. The editing forms are displayed when editing documents on the **Form** tab in the **Pages** application. | | ---------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Forms | Allows the control to be used for the fields of [forms](https://docs.kentico.com/k8/managing-website-content/forms.md), which you can edit in the **Forms** application. If you wish to make the form control available in the [Form builder](https://docs.kentico.com/k8/managing-website-content/forms/designing-forms-using-the-form-builder.md), you need to enable the **High priority** flag.
If you allow a form control for forms, you also need to enter the following default values:
**Default data type** - the data type of the field used by default when a user chooses to create a new field of this type.
**Column size** - only applies to the _Text_ data type. Sets the maximum size of the database column used to store the field, which also limits number of characters that may be entered into the field. | | Custom tables | Allows the control in [custom table](https://docs.kentico.com/k8/developing-websites/defining-website-data-structure/custom-tables.md) fields, which you can edit in **Custom tables -> edit custom table -> Fields**. The corresponding data editing form is displayed in the **Custom table data** application. | | System tables | Allows use in the fields of system objects. You can edit the fields in **Modules -> Edit module -> Classes -> Edit class -> Fields**. The editing forms of system objects are located in various sections of the administration interface or on the live site. | | Reports | Allows the control for the user interface of [report parameters](https://docs.kentico.com/k8/configuring-kentico/working-with-system-reports/defining-report-parameters.md), which you can define in **Reporting -> edit a report -> Parameters**. The reporting parameter form is displayed when viewing reports in the administration interface or on the live site. | | Controls and web parts | Allows the control to be used for the properties of [web parts](https://docs.kentico.com/k8/custom-development/developing-web-parts.md) and [widgets](https://docs.kentico.com/k8/developing-websites/preparing-widgets-for-users.md), as defined in the **Web parts** or **Widgets** applications. This editing form provides the configuration dialog of individual web parts or widget instances. | ## Defining form control parameters On the **Properties** tab of the form control editing interface, you can define parameters. See [Defining form control parameters](https://docs.kentico.com/k8/custom-development/developing-form-controls/defining-form-control-parameters.md) for further information. ## Previewing form controls When editing form controls, you can use the **View** tab to check the appearance of the control in a sample 1-field form.