Umbraco Forms
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Adding A Field Type To Umbraco Forms

This builds on the "adding a type to the provider model" chapter


Add a new class to the Visual Studio solution, make it inherit from Umbraco.Forms.Core.FieldType, and fill in the constructor:
using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.AspNetCore.Http;
using Umbraco.Forms.Core.Enums;
using Umbraco.Forms.Core.Models;
using Umbraco.Forms.Core.Services;
namespace MyFormsExtensions
public class MyCustomField : Umbraco.Forms.Core.FieldType
public MyCustomField()
Id = new Guid("08b8057f-06c9-4ca5-8a42-fd1fc2a46eff"); // Replace this!
Name = "My Custom Field";
Description = "Render a custom text field.";
Icon = "icon-autofill";
DataType = FieldDataType.String;
SortOrder = 10;
SupportsRegex = true;
FieldTypeViewName = "FieldType.MyCustomField.cshtml";
// You can do custom validation in here which will occur when the form is submitted.
// Any strings returned will cause the submission to be considered invalid.
// Returning an empty collection of strings will indicate that it's valid to proceed.
public override IEnumerable<string> ValidateField(Form form, Field field, IEnumerable<object> postedValues, HttpContext context, IPlaceholderParsingService placeholderParsingService, IFieldTypeStorage fieldTypeStorage)
var returnStrings = new List<string>();
if (!postedValues.Any(value => value.ToString().ToLower().Contains("custom")))
returnStrings.Add("You need to include 'custom' in the field!");
// Also validate it against the default method (to handle mandatory fields and regular expressions)
return base.ValidateField(form, field, postedValues, context, placeholderParsingService, fieldTypeStorage, returnStrings);
In the constructor, or via overridden properties, we can specify details of the field type:
  • Id - should be set to a unique GUID.
  • Alias - an internal alias for the field, used for localized translation keys.
  • Name - the name of the field presented in the backoffice.
  • Description - the description of the field presented in the backoffice.
  • Icon - the icon of the field presented in the backoffice form builder user interface.
  • DataType - specifies the type of data stored by the field. Options are String, LongString, Integer, DataTime or Bit (boolean).
  • SupportsMandatory - indicates whether mandatory validation can be used with the field (defaults to true).
  • MandatoryByDefault - indicates whether the field will be mandatory by default when added to a form (defaults to false).
  • SupportsRegex - indicates whether pattern based validation using regular expressions can be used with the field (defaults to false).
  • SupportsPreValues - indicates whether prevalues are supported by the field (defaults to false).
  • FieldTypeViewName - indicates the name of the partial view used to render the field.
  • RenderInputType- indicates how the field should be rendered within the theme, as defined with the RenderInputType enum. The default is Single for a single input field. Multiple should be used for multiple input fields such as checkbox lists. Custom is used for fields without visible input fields.
You will then need to register this new field as a dependency.
using Umbraco.Cms.Core.Composing;
using Umbraco.Cms.Core.DependencyInjection;
using Umbraco.Forms.Core.Providers;
namespace MyFormsExtensions
public class Startup : IComposer
public void Compose(IUmbracoBuilder builder)

Partial view

Then we will start building the view for the default theme of the Form at Views\Partials\Forms\Themes\default\FieldTypes\FieldType.MyCustomField.cshtml.
The file name for the partial view should match the value set on the FieldTypeViewName property.
@model Umbraco.Forms.Web.Models.FieldViewModel
<input type="text" name="@Model.Name" id="@Model.Id" class="text" value="@Model.ValueAsHtmlString" maxlength="500"
@{if (string.IsNullOrEmpty(Model.PlaceholderText) == false) { <text> placeholder="@Model.PlaceholderText" </text> }}
@{if (Model.Mandatory || Model.Validate) { <text> data-val="true" </text> }}
@{if (Model.Mandatory) { <text> data-val-required="@Model.RequiredErrorMessage" </text> }}
@{if (Model.Validate) { <text> data-val-regex="@Model.InvalidErrorMessage" data-val-regex-pattern="@Html.Raw(Model.Regex)" </text> }} />
This will be rendered when the default theme is used.
If working with Umbraco 9 or earlier versions, you'll find the Views\Partials\Forms\Themes\default\ folder on disk and can create the files there.
For Umbraco 10 and above, we've moved to distributing the theme as part of a Razor Class Library so the folder won't exist. However, you can create it for your custom field type. If you would like to reference the partial views of the default theme, you can download them as mentioned in the Themes article.

Umbraco backoffice view

The final step involves building the HTML view which will be rendered in Umbraco as an example of how our end result will look:
type="text" tabindex="-1"
style="max-width: 100px"
In the HTML you can access settings via field.settings, e.g. {{field.settings.Caption}} to render a "Caption" setting. It is also possible to access prevalues via field.parsedPreValues.
For built-in field types, Umbraco Forms look for this file in the virtual folder: App_Plugins\UmbracoForms\backoffice\Common\FieldTypes\. It will expect to find a file with a name matching the class's name, i.e. mycustomfield.html.
To store in a different location, you can apply the following override to the custom field type's C# representation:
public override string GetDesignView() =>

Field settings

Field settings that will be managed in the backoffice by editors creating forms using the custom field type can be added to the C# class as properties with a Setting attribute:
[Setting("My Setting", Description = "Help text for the setting", View = "TextField", SupportsPlaceholders = "true", DisplayOrder = 10)]
public virtual string MySetting { get; set; }
The property Name names the setting in the backoffice with the Description providing the help text. Both of these are translatable by providing a user or package language file containing appropriate keys:
<area alias="formProviderFieldTypes">
<key alias="mySettingName">My Setting</key>
<key alias="mySettingDescription">Help text for the setting</key>
The area aliases for the other provider types are as follows:
  • Data sources - formProviderDataSources
  • Export types - formProviderExportTypes
  • Prevalue sources - formProviderPrevalueSources
  • Recordset actions - formRecordSetActions
  • Workflows - formProviderWorkflows
The View attribute defines the client-side view used when rendering a preview of the field in the form's designer. Umbraco Forms ships with a number of these, found in a virtual path of App_Plugins\UmbracoForms\backoffice\Common\SettingTypes\.
Again though, you can use your own location, and configure with a full path to the view, e.g.:
To reference the file the setting should be configured with a full path to the view, e.g.:
[Setting("My Setting",
Description = "Help text for the setting",
View = "~/App_Plugins/UmbracoFormsCustomFields/backoffice/Common/SettingTypes/mycustomsettingfield.html",
SupportsPlaceholders = "true"
DisplayOrder = 10)]
public virtual string MySetting { get; set; }
SupportsPlaceholders is a flag indicating whether the setting can contain "magic string" placeholders and controls whether they are parsed on rendering.
HtmlEncodeReplacedPlaceholderValues takes effect only if SupportsPlaceholders is true. It controls whether the replaced placeholder values should be HTML encoded (as is necessary for rendering within content from a rich text editor).
IsMandatory if set to true will provide client-side validation in the backoffice to ensure the value is completed.

Settings when inheriting

When creating a field or other provider type, you might choose to inherit from an existing class. This could be if one of the types provided with Umbraco Forms almost meets your needs but you want to make some changes.
All setting properties for the Forms provider types are marked as virtual, so you can override them and change the setting values:
[Setting("My Setting", Description = "My custom help text for the setting", View = "TextField", SupportsPlaceholders = "true", DisplayOrder = 10)]
public override string MySetting { get; set; }
If you want to hide a setting in your derived class you can use the IsHidden property:
[Setting("My Setting", IsHidden = true)]
public override string MySetting { get; set; }

Backoffice entry rendering

The third and final client-side view file used for settings is in the rendering of the submitted values for the field in the "Entries" section of the backoffice.
These are defined by the RenderView property of a field type and are found in App_Plugins\UmbracoForms\backoffice\Common\RenderTypes\.
As for the other files, if you require a custom render type view, it's better to host them in a different location, such as App_Plugins\UmbracoFormsCustomFields\backoffice\Common\RenderTypes\mycustomrenderfield.html.
To reference the file you should override the RenderView property, e.g.:
public override string RenderView => "~/App_Plugins/UmbracoFormsCustomFields/backoffice/Common/RenderTypes/mycustomrenderfield.html";