Dynamic Field Dependencies in Select Fields

What is this for?

This guide explains how to make a Select field dynamically filter its options based on what the attendee chooses in another Select field. This is useful for cascading dropdowns like Country → City, Category → Subcategory, or Brand → Model.

Enabling Dynamic Field Mode

In the Form Constructor, open the settings panel for a Select field. You will see three checkboxes:

• Required — makes the field mandatory.
• Multiselect — allows multiple selections.
• Dynamic field — enables dependency logic (this is the one we need).

Important: The Multiselect and Dynamic field options are mutually exclusive. You cannot enable both at the same time. If you check Dynamic field, Multiselect will automatically uncheck (and vice versa).

Check Dynamic field. A new section Create dynamic depend appears below the catalog selector.

Step 1: Choose the Dependent Field

In the Select depend field (single select field) dropdown, pick the field that will act as the trigger.

Requirements for the trigger field:

• It must be a Single Select field (not Multiselect, not Dynamic).
• It must already exist in the form.
• It cannot be the same field you are currently editing.

Note: If the dropdown is empty, add a regular Select field to the form first, then come back here.

Step 2: Add a Dependency Rule

Click the green Add button (plus icon) to create your first rule. A rule block appears with two settings:

A. Select depend dictionary value

This dropdown loads dictionary values (catalog items) from the catalog assigned to the trigger field. Choose the specific value that will act as the condition.

Example: If the trigger field is Country and its catalog contains "Ukraine", "Poland", "Germany", select "Ukraine" here.

B. Select set catalog list

This dropdown shows all catalogs available in your workspace. Choose the catalog whose dictionary items should appear in the dynamic field when the condition is met.

Example: You have a Cities catalog with cities from multiple countries. Select Cities here. When the attendee picks "Ukraine" in the Country field, the dynamic field will show only Ukrainian cities from the Cities catalog.

Step 3: Add More Rules (Optional)

You can create multiple rules for the same trigger field. Click Add again to define another value → catalog pair.

Example:

• Rule 1: If Country = Ukraine → show Cities catalog
• Rule 2: If Country = Poland → show Cities catalog
• Rule 3: If Country = Germany → show Cities catalog

Each rule has its own Delete button (trash icon), visible only when there is more than one rule.

How It Works for Attendees

1. The attendee sees the trigger field (e.g., Country) with all options available.
2. The dynamic field (e.g., City) is initially disabled and shows no options.
3. When the attendee selects a value in the trigger field (e.g., "Ukraine"), the dynamic field becomes enabled and loads only the dictionary items from the linked catalog that match the rule.
4. If the attendee changes the trigger field to another value (e.g., "Poland"), the dynamic field instantly refreshes with the corresponding catalog items.

Important Rules & Limitations

Note: The dynamic field must have a catalog assigned in its own settings (the Select field catalog dropdown visible before enabling Dynamic field). Without a catalog, there are no dictionary items to filter.

Note: The trigger field can only be a Single Select field. Multiselect fields, other dynamic fields, and fields of different types are excluded from the dropdown.

Note: Circular dependencies are prevented — the current field is hidden from the trigger field dropdown.

Note: If you later delete the trigger field from the form, the dependency rules stop working. The dynamic field will remain disabled. Update or remove the rules first.

Note: The help icon (question mark) next to the section title opens this guide inside the app.

Common Questions

Why is the "Select depend field" dropdown empty?

• There are no other Single Select fields in the form.
• All other Select fields are Multiselect, Dynamic, or this same field.

Why is the dynamic field stuck in a disabled state?

• You haven't added any dependency rules yet (click Add).
• The trigger field doesn't have a catalog assigned, so there are no dictionary values to choose from.
• The catalog selected in a rule contains no dictionary items.

Can I use a text field or checkbox as the trigger? No. Only Single Select fields are supported as triggers.

What happens if I change the trigger field's catalog after setting up rules? Existing rules will reference the old dictionary values. You should review and update the rules to match the new catalog's values.

Can I show/hide the dynamic field instead of filtering its options? Currently the only supported action is filtering options (showing a subset of a catalog). Show/hide logic is planned for a future version.