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Document Understanding Activities

Last updated Apr 16, 2025

Validating documents with App actions

This quickstart guide helps you start validating documents by adding the Validation Station within UiPath® Action apps, and then sending them out for validation through Action Center as App actions. The tutorial uses UiPath Studio to automate the document processing, UiPath Apps to for displaying the validation station, and Action Center for performing the validation. The document type that is used in the examples throughout this tutorial is a health insurance form, of type CMS 1500 claim form.

The overview steps of this quickstart guide are:

  1. Build the Action app that displays the Validation Control.
  2. Use a previously configured app to design the Studio automation that processes the document, and sends it out for validation in Action Center.
  3. Complete the action within Action Center.

Steps

1. Build an Action app

Prerequisites

Make sure your tenant:

  • Has sufficient Robot units since the app runs using Serverless robots.
  • A Serverless robot template is created in Orchestrator and provisioned. For more information on serverless robots and adding them to a tenant, visit Executing unattended automations with Serverless robots.

1. Create an Action app

Note: Unlike VB apps available via the Apps service, apps can be accessed through Studio Web.

To create an Action app, follow these steps:

  1. Go to Studio Web.
  2. Select Create New > App to create a new project.
  3. Within the Project Explorer of your app, select Add pages, workflows, controls, integrations > Action.

    This step adds an Action to your app, and lets you configure an action schema for it.

  4. Expand Action, and select ActionSchema.

    Configure the action schema with the In and Out arguments that you want for App actions in Action Center.

    1. For Outcomes, add other custom outcomes that you want the action to have.

      For example, you can add the a custom outcome, named "Approve".

    2. For Input Properties, add properties for data that you want to pass into the action.

      These properties will appear in the Create App Task activity, when this app is selected from the Apps dropdown list. Input properties allow you to pass data from your Studio automation to your action.

    3. For Output Properties, add properties for arguments that you want to retrieve from the action.

      These properties will be accessible from the Wait for App Task and Resume activity, through the Task Object (Output) variable.

    4. For Input/Output properties, add properties that function as In/Out arguments in your Studio automation.

      These Input/Output properties first appear as properties in the Create App Task activity, that you pass to the action. And then, after the action is completed, you can access the same properties, that were updated, from the Wait for App Task and Resume activity, through the Task Object (Output) property.

2. Add and customize the Validation Control

A Validation Control incorporates the Validation Station, used in document processing workflows. To add and customize a Validation Control within an Action app, follow these steps:

  1. Open the desired Action app, where you want to incorporate the Validation Station.
  2. Select Open toolbox.
  3. Under Display, find the Validation Control, and add it into your app.
    Adding the Validation Control to your app automatically creates a Var<ValidationControl_PageName> variable under the App variables section from your app's Project Explorer.
    Note: You can use the Validation Control and the corresponding App Variable to read information from the Validation Control. Use the Var<ValidationControl_PageName> App Variable to write information to it.
  4. Prepare the action schema:
    1. In the Project Explorer, under Action, select ActionSchema.
    2. In the Input Properties, select Add property.
    3. In the property search bar, select More Options.
    4. Under Advanced, select ContentValidationData.
      This is the input property that will display in the Create App Task activity. The ContentValidationData input property requires a ContentValidationData object as input, which can be a single object or an array/list of ContentValidationData instances. ContentValidationData contains the artifacts of the Validation Station. ContentValidationData is created using the Create Document Validation Artifacts activity.
  5. Configure the Validation Control:
    1. Go to the Validation Control properties.
    2. In the Source input, select the Action input that you have defined as a ContentValidationData type.
  6. Configure the rest of the app with other Controls that you need.

3. Access Validation Control Data and its properties

Various properties of the Validation Control, such as Taxonomy, Extraction Result, Selected Document Type, Selected Field, and Data Source, can be accessed using the Validation Control variable (VarValidationControl_PageName). You can change the values displayed in the Validation Control through the corresponding app variable. Follow the steps outlined under Edit Validation Control data to add, modify, or remove a field value.

The following table describes the properties that you can access from the Validation Control, their data type, and descriptions.

Table 1. Validation Control properties
PropertyData TypeDescription
TaxonomyUiPath.DocumentProcessing.Contracts.Taxonomy.DocumentTaxonomyThe taxonomy object with which the content was prepared for display. It contains information about document types, fields, and display properties.
ExtractionResultUiPath.DocumentProcessing.Contracts.Results.ExtractionResultThe extraction results, as they are (with or without human changes), from the Validation Control.
SelectedDocumentTypeSystem.StringThe name of the document type currently selected in the Validation Control.
SelectedFieldUiPath.DocumentProcessing.Contracts.Apps.FieldValueDetailsThe field currently selected in the Validation Control along with its value.
DataSourceUiPath.DocumentProcessing.Contracts.Actions.ContentValidationDataThe content validation data that is currently the source of the Validation Control.
HiddenbooleanThe state of the control property governing whether the control is visible or hidden.
DisabledboolanThe state of the control property governing whether the control is editable or not.
IsValidbooleanChecks validity of the Validation Control value. If true, indicates it is valid.

4. Edit Validation Control data

You can change the values displayed in the Validation Control through the corresponding app variable. For example, you can change Extraction Result values displayed in the Validation Control through the corresponding app variable.

The following example shows how to update a regular field value:

  1. Select any Control in your app, and go to Events.
  2. Select Define automation.

    This action opens Studio Web's designer panel, where you can build a trigger automation for a certain app control.

  3. In the context of the document's Extraction Results, to add or change a field value for regular fields, add a Set Variable Value activity in the automation.
    1. For the To Variable field, use AppVariable.VarValidationControl_PageName.Field("<field name>").Value.
      This expression represents the field you want to change, accessed through the VarValidationControl_PageName variable.
    2. In the To field enter the desired value for the referenced field.
    Apart from regular fields, the AppVariable.VarValidationControl_PageName variable can also manipulate multi-value fields using AppVariable.VarValidationControl_PageName.Field("<field name>", <index>), and interact with table cells using AppVariable.VarValidationControl_PageName.Field("<table field name").Field("<column name>", <row index>).
    To delete values, select the target value similarly and use the .DeleteValue flag set to True.

    The properties of values that you can update in the validation control include:

    • Textual value (.Value)
    • Confirmed state (.Confirmed)
    • Confidence level of the value (.Confidence)
    • Deletion flag (.DeleteValue)
    • Flag to remove a value reference (.KeepReference)
You can use the same steps for changing other Validation Control data at runtime. The only difference is that you use a different variable, in the To Variable field, so it corresponds to the Validation Control data you want to change. For example, you can use AppVariable.ValidationControl.SelectedDocumentType variable if you want to update it with a different value.
Figure 1. The Set Variable Value activities through which you can update data from the Validation Control

5. Create events for the Validation Control

You can trigger various events specific to the Validation Control. In the Project Explorer, navigate to the Validation Control, and select it. The Events panel of the Validation Control allows you to define automations for specific events.

The following table describes the available Validation Control events:

Table 2. Validation Control events
EventDescription
On ReadyTriggers when the Validation Control is loaded.
Document Type ChangedTriggers when the user changes the document type from the Validation Control.
Field SelectedTriggers when the user selects one of the fields, or the value of a field, in the Validation Control.
Field Value ChangedTriggers when the user adds, removes, or replaces a field value in the Validation Control.

6. Use dedicated Validation Control activities

You can use specific activities dedicated to working with the Validation Control, from the AppEvents.Activities package:
  1. Set Validation Control Field Focus: Allows you to focus on a field, based on a configured event.
  2. Save Validation Control State: Saves the state of the Validation Control. You can use this when you want to revisit and complete the validation later.

Common Validation Control expressions

When you are creating your app that contains a Validation Control, you can use the following expressions to access various data exposed by the Validation Control. The following table describes the most common expressions you can use when working with the Validation Control:

Table 3. Common Validation Control expressions
PurposeExpression
Access Extraction Results displayed within the Validation Control
  • AppVariable.VarValidationControl_PageName.ExtractionResult
  • MainPage.ValidationControl.ExtractionResult
Access the taxonomy loaded in the Validation Control
  • AppVariable.VarValidationControl_PageName.Taxonomy
  • MainPage.ValidationControl.Taxonomy
Access the selected field in the Validation Control
  • AppVariable.VarValidationControl_PageName.SelectedField
  • MainPage.ValidationControl.SelectedField
The properties of the selected field can be:
  • Field.FieldName – Field name.
  • Field.FieldType – Field type.
  • Field.ValidatorNotes – The field's validator notes.
  • Field.Values – All values of a selected field.
  • Field.Value – Information related to the field value:
    • FieldValue.Value
    • FieldValue.Confidence
    • FieldValue.OperatorConfirmed
    • FieldValue.FieldValueIndex (for multi-value fields returns the index that the selected Field Value is pertaining to).
Access additional Validation Control propertiesMainPage.ValidationControl.<PropertyName>
Read Extraction Results dataUse the methods exposed by the Extraction Result class.
Read taxonomy dataUse the methods exposed by the Taxonomy class.
Access a field value to update it in the Validation Control AppVariable.<ValidationControlVariable>.Field("<FieldName>").Value
Retrieve the list of field names displayed in the Validation Control AppVariable.<ValidationControlVariable>.ExtractionResult.GetFields().Select(Function(f) f.FieldName)

6. Publish and deploy the app

After you build your Action app and trigger automations for Controls inside of it, you can publish it. Publishing the app makes it available to use for creating App actions. For more information on publishing apps, visit Publishing, deploying, and upgrading app projects.

2. Create Studio automation

Prerequisites

  • Install the following activity package versions:
    • IntelligentOCR.Activities version 6.24.0
    • Persistence.Activities version 1.5.5 or higher.
    • AppEvents.Activities version 3.12.0 or higher.
  • Create a storage bucket in Orchestrator, in the same folder where you want to publish the document processing automation.

    Data required to load the Validation Control within apps is stored within an Orchestrator storage bucket.

  • Add the document that you want to process inside the Studio project folder.
  • Optionally, if you want to use generative extraction or validation capabilities, then you need AI units. For more information on Document Understanding generative features, visit Generative features.

1. Process a file using Document Understanding

Add activities that use Document Understanding to process a file. Prepare the document for validation in Action Center, through apps, using digitization and extraction.

After adding the activities for processing the file, the following variables should be available:

  • DocumentTaxonomy (Taxonomy): Retrieved via the Load Taxonomy activity.
  • Dom (Document Object Model) and text (Document Text): Acquired through the Digitize Document activity.
  • doc (Document Path): Represents the path to the processed file.
  • autoExtractionResults (ExtractionResults): This is the output from the Data Extraction Scope activity, regardless of the extraction methods used.

2. Send out the validation information to the app

After the document is ready to be validated, you can prepare all the information to be sent out to the previously created and deployed app. Follow these steps:

  1. Add a Create Document Validation Artifacts activity to create the Content Validation Data object which stores the information necessary for loading the Validation Control within the Action app.
    In this example, configure the activity using the previously created or outputted variables:
    • Bucket Folder Path: The name of the Orchestrator folder where the storage bucket was created.
    • Bucket Name: storageBucketName
    • Bucket Directory Path: The directory path within the previously inputted storage bucket, where you want to store action data.
    • DocumentPath: doc
    • Document Text: text
    • Document Object Model: dom
    • Taxonomy: taxonomy
    • Automatic Extraction Results: autoExtractionResults
  2. Add a Create App Task activity, so you can bind the Content Validation Data object to the previously designed app and then send it out to Action Center for validation.

    In this example, configure the activity as follows:

    • Title: CVD
    • Priority: Medium
    • Apps: Demo.Validation.Control.in.Apps
    • App Version: v2.0.0

      After you select the App, and the corresponding version that you want to use for creating the action, the input properties of that app will be shown in the body of the activity.

      • In this example, one of the input properties is Action_Content_Validation_Data, which requires the document validation artifacts previously created: contentValidationData.
    Figure 2. The Create App Task activity

  3. Add a Wait for App Task and Resume activity to return the information about the action, and resume the workflow.

    In the Created App Task field, enter the output variable of the Create App Task activity.

  4. Add a Retrieve Document Validation Artifacts activity, to return the document validation artifacts after the user performed validation in Action Center.

    Pass the output variable of the Create Document Validation Artifacts activity as the input of the Retrieve Document Validation Artifacts activity.

    Tip: You can also create dedicated output variables for additional information stored in the validation artifacts, such as AutomaticExtractionResults, and ValidatedExtractionResults.

3. Perform validation in Action Center

  1. Open Action Center, and go to My Actions or Manage Actions.
  2. In the Unassigned tab, find the action you just created using the previous Studio automation.
  3. If you want to assign the action to yourself, select the desired action, and then select Assign to self.
  4. If you want to assign the action to another user, select More options for the desired action. Then select Assign to user, and select a user from the dropdown list.
  5. Go to the Pending tab, and complete the action, so the Studio workflow can be resumed.
  • Steps
  • 1. Build an Action app
  • 2. Create Studio automation
  • 3. Perform validation in Action Center

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