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Forms - How to conditionally make form fields mandatory

How can we apply conditional validation to a form - for example, if the status is closed, a closed date must be entered? In this post, we'll look at a quick and simple way to add this type of conditional, mandatory field validation to a form.

In this post, we’ll cover a quick and simple way to conditionally make a form fields mandatory.

Example scenario

To demonstrate this technique, we’ll apply this to a form that displays a property record. Each record optionally stores an acquisition price and an acquisition date.

Our requirement is this - if a user enters an acquisition price, the acquisition date field becomes mandatory. Vice versa, if the user enters an acquisition date, the acquisition price field becomes mandatory.
 

Creating a Form

To begin, we’ll create an ‘auto-generated’ app using the start from data option. This generates the following edit form.
Each card in the form contains a ‘Required’ property. When this is set to true, the card will mandate the entry of a value. We can set the value of this to a formula that references the data entry text input controls.
 

Editing the Data Entry Cards

Taking the form in this example, we’ll begin by modifying the required property in the acquisition price card. We unlock the card and set the required property to the following formula:

Not(IsBlank(DataCardValue12.SelectedDate))

Here, DataCardValueValue12 refers to the date picker control inside the acquisition date card. We can determine the name of this through the tree view control.

The conditional formula tests the value that the user enters into the date picker control. If this is not blank, the resulting expression resolves to true and the acquisition price card becomes ‘required’.

 
Next, we carry out the same process on the acquisition date card. We unlock the card, and set the required property to the following formula:

Not(IsBlank(DataCardValue13.Text))

Running our App

We can now run our app and the validation will work as expected. If we were to create a new record, as soon as we enter an acquisition price, an asterix symbol will appear to the left of the acquisition date label to indicate that that the field is mandatory. If we attempt to save the record without entering an acquisition date value, the app will show an error message beneath the acquisition date field and in the banner.

Conclusion

We can quickly add conditional validation to form fields by using formula to set the required property of form cards.

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