Hi is it possible in EpiServer Forms to create a validation message on a form element? I want to create a warning message when an element hasn't been set to required when publishing the element.
This is a validaton message in the episerver backend, not in the front end (website).
If you create the standard IValidate class for the element you want you should be able to add custom validation which will be triggered when trying to publish. As per standard with IValidate you can raise these as errors, warnings or information. http://www.jondjones.com/learn-episerver-cms/episerver-developers-guide/common-web-page-component-tutorials/how-to-return-different-validation-warnings-to-content-editors-when-publishing-content-in-episerver