asp.net core validation summary
@model RegisterViewModel
<form asp-controller="Demo" asp-action="RegisterValidation" method="post">
<div asp-validation-summary="ModelOnly"></div>
Email: <input asp-for="Email" /> <br />
<span asp-validation-for="Email"></span><br />
Password: <input asp-for="Password" /><br />
<span asp-validation-for="Password"></span><br />
<button type="submit">Register</button>
</form>