Calling a pagemodel/controller with ajax is possible, but it is not well documented.
Steps done in this project:
Add jquery, jquery-unobtrusive-ajax, jquery-validation and jquery-validation-unobtrusive to your scripts lib in wwwroot
Add NuGet package Microsoft.jQuery.Unobtrusive.Ajax to project (and Microsoft.jQuery.Unobtrusive.Validation)
Add handler to your pagemodel, for example "public async Task<IActionResult> OnPostSaveFormAsync()" or "public IActionResult OnPostSaveForm()"
Return in that method a new PartialViewResult() (viewname="submitsuccess") and create a partial (submitsuccess.cshtml)
In main form (for example in Index.cshtml) add a form (or scaffold from model) with the form element like:
<form id="thanks" asp-page-handler="SaveForm" data-ajax="true" data-ajax-method="POST" data-ajax-mode="replace" data-ajax-update="#thanks" data-ajax-loading="#loading" data-ajax-success="Success" data-ajax-failure="Failure">
#thanksis the element to replace with result from partial on success, here I replace the form (notice theid="thanks")#loadingis the element to show when call is in progress
Use [BindingProperty] on your pagemodel class for the model, for example
[BindProperty] public ContactForm ContactForm { get; set; }
Please see this repo for an example: https://github.com/psijkof/RazorPagesAjax
Thanks to @AmTute (https://github.com/AmTute/VS2017AjaxFormExample) for his example repo. It helped me to create a working sample for Asp Net Core Razor Pages!