Hi Huw

Thanks for the help.

My current issue is that I'm not sure how to proceed. What I have been trying so far is to pass my descendant model via the form seen on image 1 and then I wanted to let the annotations in the class handle the validations for me and then return those errors to the form validation message fields.

If I do a simple submit on my form it does what I want it to do except it returns my partial and replaces my website with that only. I need to only update the form content to show my errors. If that is the correct thing to do here.

I did another attempt with trying to pass on the descendant model using ajax but here it seems like I can only pass on form data and them I'm lost on how to do the validations I mentioned above

Image 3 was only for showing the method I have been trying for handling/returning my errors but I have yet to find the correct way to do this.

I hope this gave some more insight to my issue. Its not that I get any errors, I'm simply at a loss on how to proceed with finding a solution.

I tried your solution and it got me some of the way. It will now return and update only the content in step/form but it gives me an error.

I had to include the [FromBody] or the function would get the form data. But this is what I ended up with.

[HttpPost]
public IActionResult CreateClaimRequest([FromBody]PolicyAndContactInfoStep infoStep)
{
    if (ModelState.IsValid)
    {
        return Ok("SUCCESS");
    }
    else 
    {
        return PartialView("~/Views/Partials/stepTemplates/PolicyAndContact.cshtml", model:infoStep);
    }
}

The error that is returned to the page is

Umbraco.Cms.Web.Common.ModelBinders.ModelBindingException: Cannot bind source type UmbracoProject.Models.PolicyAndContactInfoStep to model type Umbraco.Cms.Core.Models.PublishedContent.IPublishedContent

The model I'm trying to return is not the current model of my page but a descendant model used to contain just that one part of the form. Do I have to include something extra for it update properly?

I think this error is caused by your PartialView("~/Views/Partials/stepTemplates/PolicyAndContact.cshtml", model:infoStep).

If I am correct, then your PolicyAndContact.cshtml view is expecting an IPublishedContent (due to model IPublishedContent or inherits UmbracoViewPage on top). But you are now passing a PolicyAndContactInfoStep that cannot be cast to an IPublishedContent.

Is it possible to pass my IPublishedContent to the controller through ajax or how do I manage to return data in the correct format?

your partial view PolicyAndContact.cshtml needs it's model to be PolicyAndContactInfoStep rather than inheriting umbracoviewpage models.

Ajax is just posting a html form, it doesn't know about publishedcontent, just form values.

Why do you need pass the IPublishedContent in the controller?

The thing is I don't know if it should. I have been trying to get the ajax to return something useful for me so I can update the form content to show my annotations/errors.

From your last comment I believe this is wrong then:

@inherits UmbracoViewPage

@{

    PolicyAndContactInfo pacModel = Model.Descendant<PolicyAndContactInfo>();

}

Since its a partial view I thought it could only inherit from its 'parent' and not have a model of its own but I understand now that I might have misunderstood that?

no, it will have a model of it's own

so use @model PolicyAndContactInfoStep (that is what your controller is using) instead of @inherits UmbracoViewPage

If you need to upadte your I published content in the controller then you will probably want to include the publishedcontents id in a hidden field so that you can retreive it in your controller.

Thank you.

I will give this a shot and see how it goes :)