Often, you may need to display some text or dynamically calculate a value.

For example, you may want to show different text in a field based on what the user has previously answered, or maybe you have a product order Form that should calculate the total amount to pay.

This is where the Dynamic Value property found on most form fields comes in handy.

Dynamic Value allows you to create a formula that generates or calculates a result that is assigned as the given field’s answer.

Handling calculations

For example, imagine you have the following Form fields:

• “Enter Product Name” – a Text field with Dataname of productName
• “Enter Product Cost” – a Number field with Dataname of productCost
• “Enter Number of Items” – a Number field with Dataname of numberItems

1. Add a new Hidden field to your Form, and set the Dataname to be totalIncludingTax
2. On this new field, find the Dynamic Value property.
   Its found under the Validation & Behavior property section of a field.
3. Enter the following formula into the Dynamic Value:
   {{productCost}} * {{numberItems}} * 1.10

What we’ve done so far is add a hidden field (a field the app user will never see) which will store the result of the formula calculation. The formula is applying a 10% tax rate to the product cost amount. This field’s value can now be used in other fields in the form and output.

This is the first example of how you can use the Dynamic Value property to calculate results.

Joining static and dynamic text

Now we’re going to use Dynamic Value again to display a message to the app user. We want to summarise their order details using a read-only Text field.

1. Add a new Text field to your Form, set the Data Name to be “orderSummary”.
2. Find the Read Only property and tick the box.
   This will make the field read-only, so the user cannot change the displayed answer text.
3. Find the Dynamic Value property and enter the following formula:
   CONCAT('You ordered ', {{numberItems}}, ' of ', {{productName}}, '. Total (including tax) is: ', {{totalIncludingTax}})

What we’re doing with the above formula is building up dynamic text, by concatenating together pieces of text.

The CONCAT() function is used to build up the final text, and we are using the values from the various fields (the {{dataName}} bits).

Supporting articles

Formula Cheat Sheet

Creating a Formula

Formula Quick Question/Answer Reference