I have a form block that has its own PostSubmissionActorBase which will submit data to an external API with the form data. One of the fields i need to submit is the current locale of the submission however when i get the CultureInfo.CurrentCulture inside the PostSubmissionActorBase it is always set to the default locale "en".

A soloution i had was to add a hidden input element to the FormContainerBlock.cshtml this sets the correct value in the browser but when clicking submit the input isn't set with the payload to /EPiServer.Forms/DataSubmit/Submit. I could create my own custom element property block but this will then have to be added manually to every form.

        <input type="hidden" class="Form__Element Form__SystemElement FormHidden FormHideInSummarized" name="__CultureCode" value="@CultureInfo.CurrentCulture.Name" data-f-type="hidden" autocomplete="off" />