File Picker Form Element

The File Picker form element allows the user to select one or more files from the file system.

To use a file picker, the user clicks Add File (), selects one or more files (), and then clicks Open. The selected files () are listed on the form. If the user picked fewer files than the maximum that you configured, then the user can click Add File again and select additional files. To remove a file from the list, the user clicks the file's Delete button.

Example of the File Picker form element, shown in a Geocortex viewer

File Picker Properties

The following table describes the properties of the File Picker 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 File Picker Form Element

Button Label

Type: String

The text that appears on the button that the user clicks to select a file. The default text is Add File.

You can format the button's label using Markdown.

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.filePicker1.visible

Enabled

Type: Boolean

Name in Properties Panel: Enabled

Name to Use in Expressions: enabled

Indicates whether the file picker is enabled in the running workflow. When a file picker is enabled, the user can select files. When a file picker is disabled, the user can see the file picker but cannot interact with it. Disabled elements appear dimmed or shaded in the running workflow.

By default, file pickers are enabled. To disable a file picker initially, clear the Enabled checkbox. You may want to change the property's value at run time depending on the user's input in a previous form element.

To access the enabled property in an expression:

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

For example:

$form1.state.filePicker1.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.

File Types

Type: String

Name in Properties Panel: File Types

Name to Use in Expressions: fileTypes

The types of files that the user can select. Use commas to separate the file types. If you leave the File Types property blank, the user can select any type of file.

You can specify either file extensions or MIME types, for example:

  • .xml - Accepts XML files

  • .png, .jpg, .jpeg - Accepts PNG, JPG, and JPEG files

  • image/png - Accepts files with the image/png MIME type

  • image/* - Accepts files with an image/* MIME type

  • * - Accepts all file types

To access the fileTypes property in an expression:

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

For example:

$form1.state.filePicker1.fileTypes

Maximum Files

Type: Number

The maximum number of files that the user can select. If you do not specify the maximum, the user will be able to select 3 files.

Required

Type: Boolean

Name in Properties Panel: Required

Name to Use in Expressions: require

Indicates whether the user must select a file. When the file picker is required, the user cannot submit the form until at least one file is selected.

By default, file pickers are not required. To require a file picker, select the Required checkbox.

The Required checkbox is intended as a quick way to do simple validation without having to add a validate event. If you add a validate event to a form element, selecting the Required checkbox will not have any effect. In this case, you must make the validate event check whether the user entered a value.

To access the require property in an expression:

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

For example:

$form1.state.filePicker1.require

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.

Tooltip

Type: String

A message that displays when the user hovers the mouse pointer over the file picker. You may want to use the tooltip to provide help to the user.

type

Type: String

The variety of form element. File pickers are type "FilePicker".

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.filePicker1.type

value

Type: FilesRef

An object of type FileRef. FileRef objects have a files property that is an array of File objects.

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, file pickers 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.filePicker1.visible

File Picker Events

The following table describes the events associated with the File Picker form element. As in Workflow Designer, the events are listed in the order that they fire.

Events for the File Picker 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 change event fires when the user adds a file.

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 selection.

The change event fires every time the user adds a file. This means that the file picker'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.

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.

By default, the Required property does not work when the file picker has a validate event. If you want the workflow to perform the Required check, add a Propagate Form Event activity to the validate subworkflow. The Propagate Form Event activity instructs the workflow to perform the Required check after the validate subworkflow completes.

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

© 2019 Latitude Geographics Group Ltd. All Rights Reserved.

Documentation Version 5.11