Pre-populating Checkboxes in Gravity Forms

We previously wrote about how you can pre-populate input values in Gravity Forms.  The comments for that post revealed something obvious that we missed – the technique does not work for checkbox fields or any other fields that have pre-defined choices, such as radio buttons and dropdowns.

For this blog post, we are focusing on checkbox fields to keep things simple.  However, based on our testing the same technique will also work for radio buttons and dropdown/select elements.

Hooking Into The Right Place

In our previous post demonstrating how to pre-populate text inputs, we used the gform_field_value_{field_name} hook, in conjunction with the parameter name that we set for the field.

For checkboxes, though, it turns out that we need to use a hook that acts on a higher level and affects the entire form.  The hook we need is gform_pre_render_{id}, where {id} is the form ID being used.  So, if our Form ID were 1, we would use the hook gform_pre_render_1.

Since we’re hooking into the entire form, we have to be really careful and only alter the field(s) and the choice(s) that we want to alter.

Getting The Right Field ID

Each field in Gravity Forms is given its own ID, which will be unique within that specific form.  Take special note of the Field ID for the checkbox field that you want to pre-populate.  In our example shown below, our field is called Favorite Colors and the Field ID is 1.

Setting A Value For Each Choice

Before writing any code, let’s also make sure that we give our choices all a value, instead of relying solely on the field label.

To do this, we simply need to check the “show values” checkbox when editing our form field and then enter a value for each checkbox.

Putting It All Together

Now that we’ve got our checkbox field, we know its Field ID, and we have a value set for each choice, we can add our code which will pre-populate the checkboxes.

In our example, we are pre-populating the “Red” and “Blue” checkboxes and leaving the “Green” checkbox unchecked by default.  Of course, the user can change these as they see fit but this lets us set up the form the way we want initially.

Note that for radio and dropdown fields, only one value is allowed to be selected.  Therefore, in our example the “Blue” choice would be selected but “Red” would not.  This is because “Blue” comes later in the loop and it overrides the fact that “Red” was selected earlier.

Possible Use Cases

You might notice that Gravity Forms allows you to achieve this exact same example without using any code, by checking the checkboxes to the left of each choice within the Admin UI.

However, since our method allows us to insert our own PHP code, we can do things that allow for more dynamic situations such as having certain checkboxes checked by default based on which user is currently logged in.