Custom Form Elements

Custom form elements are developed within an organization to provide custom functionality for forms in the organization's workflows. The specific functionality provided by a custom form element is up to the organization. For example, an organization could develop a form element that presents a table with selectable rows.

Each custom form element that an organization develops is assigned a unique type. To use a custom form element, you add a Custom element to your form and set the Custom Type property to the element's unique type.

See also...

Custom Development

Custom Form Element Properties

The following table describes the properties of the Custom form element. Some properties can be configured in the Properties panel in Workflow Designer. These properties have configuration information in the table. Similarly, some properties can be accessed in expressions. These properties have information about how to access the property in an expression.

If a property can be configured in the Properties panel and accessed in expressions, the property has two names: the name that appears in the Properties panel and the name that is used in expressions. Both names are given in the table. Sometimes the names only differ in capitalization, for example, Visible (in the Properties panel) or visible (in expressions).

Properties of the Custom Form Element

Custom Type

Type: String

Name in Properties Panel: Custom Type

Name to Use in Expressions: customType

The type of custom form element. The type is specified in the custom activity that registers the custom form element.

To access the customType property in an expression:

${Display Form ID}.state.{Element ID}.customType

For example:

$form1.state.custom1.customType

Description

Type: String

A description of the element. The description appears below the element's title.

You can use the Description property to describe what the element represents or to provide instructions to the user about how to use the element.

You can format the description using Markdown.

Element ID

Type: String

The element's ID, which is used in other form elements and activities to access the element's properties, including the user's input. The ID must be unique across all elements in the form.

You cannot get or set the value of the Element ID property in an expression—you can only use the value that you configured for it. To use the Element ID property in an expression:

${Display Form ID}.state.{Element ID}.{property name}

For example:

$form1.state.custom1.visible

enabled

Type: Boolean

The code for the custom form element must implement support for enabling and disabling the element. Otherwise the enabled property will never be set.

If the custom form element supports enabling and disabling, then the enabled property indicates whether the element is enabled in the running workflow.

When a form element is enabled, the user can interact with it. When it is disabled, the user can see the form element but cannot interact with it.

To access the enabled property in an expression:

${Display Form ID}.state.{Element ID}.enabled

For example:

$form1.state.custom1.enabled

error

Type: String | MarkdownRef

Indicates whether an error occurred in the element.

MarkdownRef objects have a markdown property of type String that represents the Markdown text.

We recommend using the Set Form Element Error and Clear Form Element Error activities to work with errors in form elements.

Title

Type: String

The element's title, which appears at the top of the element.

You may want to change the title to describe what the element represents in your workflow. Descriptive titles make forms easier to understand.

You can format the title using Markdown.

type

Type: String

The variety of form element. Custom elements are type "Custom".

Use the type property to find out the variety of a form element in a form with many elements: loop through ${Display Form ID}.state, comparing each element to the known form types and performing some action on the elements that meet your type criteria.

To access the type property in an expression:

${Display Form ID}.state.{Element ID}.type

For example:

$form1.state.custom1.type

value

Type: any

The code for the custom form element must implement support for the value. Otherwise the value property will never be set.

If the custom form element supports having a value, then the value property is the element's current value.

To access the value property in an expression:

${Display Form ID}.state.{Element ID}.value

For example:

$form1.state.custom1.value

Visible

Type: Boolean

Name in Properties Panel: Visible

Name to Use in Expressions: visible

Indicates whether the element is visible to the user. By default, custom form elements are visible. If you want to hide the element initially, clear the Visible checkbox. You may want to change the visibility at run time depending on the user's input in a previous form element.

To access the visible property in an expression:

${Display Form ID}.state.{Element ID}.visible

For example:

$form1.state.custom1.visible

Custom Form Element Events

The following table describes the events associated with the Custom form element.

Events for the Custom Form Element

load

The load event fires when the element finishes loading.

You can use the load event to set one or more of the element's properties at run time.

change

The code for the custom form element must implement support for firing the change event. Otherwise the change event will never fire.

If the custom form element supports the change event, then the change event fires when the user enters some input.

You can use the change event to create dependencies between form elements. For example, you could configure a change subworkflow that enables or disables other form elements depending on the user's input.

The change event fires every time the user's input changes. This means that the custom form element's change subworkflow can run multiple times. Because of this, you should make sure that the change subworkflow is not computationally intensive or long running.

click

The code for the custom form element must implement support for firing the click event. Otherwise the click event will never fire.

If the custom form element supports the click event, then the click event fires when the user clicks a button in the custom form element.

custom

The code for the custom form element must implement support for firing the custom event. Otherwise the custom event will never fire. The code controls when the custom event fires.

validate

The validate event fires when the user clicks a button that causes validation.

You can use the validate event to verify that the user's input is valid before allowing the form to submit. If the input is not valid, use the Set Form Element Error activity to display an error to the user and prevent the form from submitting. If the input is valid, use the Clear Form Element Error activity to clear an existing error and allow the form to submit.

If you use a Set Form Element Error activity, make sure you also use a Clear Form Element Error activity to clear the error. Otherwise the form may get stuck in an invalid state.

For an example, see Example - Subworkflow for a Validate Event.

© 2018 Latitude Geographics Group Ltd. All Rights Reserved.

Documentation Version 5.9