Form designer: How to add a condition which compares a numeric field value?

If you want to add a form field behavior (such as Required) that tests a numeric field (e.g. REQUEST_AMOUNT > 1000), you have to add a condition.

You cannot use the REQUEST_AMOUNT.Text property directly because it returns a String value. Instead, you have to check if the value is not null and convert the value into an Integer or a Decimal:

!String.IsNullOrEmpty(REQUEST_AMOUNT.Text) && Convert.ToDecimal(REQUEST_AMOUNT.Text) > 1000

As well, check that the REQUEST_AMOUNT form field has a Numeric format defined.