I've spent several hours combing Stackoverflow and other sites trying everyone's solutions with no luck so far. I'm sure I've missed something, but I can't see it. Hopefully you can point me to a fix.

I have an initial form inside a partial view that is rendered into a parent view whose validation works fine. Once the form is submitted via Ajax replace, I return either a login or registration partial view with a new form in the response. This second form will not display the model validation errors when an incomplete form is submitted and the same partial view is returned.

Thanks in advance for any tips you can offer to bring an end to this insanity!

Parent View Section

<div class="row">
<div class="col-sm-8 col-sm-offset-2">
 <div class="panel panel-primary" id="formData">
 @await Html.PartialAsync("_UserNamePartial", new UserNameViewModel())
 </div>
</div>
</div>

Working Rendered Partial View

<div class="panel-heading">
<h3 class="panel-title">Let's Start With Your E-mail Address</h3>
</div>
<div class="panel-body">
<div class="row">
 <div class="col-xs-12">
 <form asp-controller="Account" asp-action="IsAccountValid" data-ajax="true" data-ajax-method="POST"
 data-ajax-mode="replace" data-ajax-update="#formData">
 @Html.AntiForgeryToken()
 <div class="form-group">
 <label for="UserName">Your Email Address</label>
 <div class="input-group">
 <input type="text" id="UserName" name="UserName" class="form-control" placeholder="Your email address" />
 <div class="input-group-btn">
 <button type="submit" id="btnGetStarted" class="btn btn-primary">Get Started</button>
 </div>
 </div>
 <span asp-validation-for="UserName" class="text-danger"></span>
 </div>
 </form>
 <div asp-validation-summary="ModelOnly" class="text-danger"></div>
 </div>
</div>
</div>

Initial Validation Controller Action

 [HttpPost]
 [AllowAnonymous]
 [ValidateAntiForgeryToken]
 public IActionResult IsAccountValid(UserNameViewModel model)
 
 if (!ModelState.IsValid)
 return PartialView("../Home/_UserNamePartial", model);

 AccountRepository accountRepository = new AccountRepository(ConnectionConfig.InshoraDev);
 AuthName match = accountRepository.GetAuthName(model.UserName);

 if (match != null)
 
 ModelState.Clear();
 LoginViewModel loginModel = new LoginViewModel()
 
 UserName = model.UserName
 ;

 return PartialView("_UserLoginPartial", loginModel);
 

 ModelState.Clear();
 SignUpViewModel signupModel = new SignUpViewModel()
 
 UserName = model.UserName,
 ;

 return PartialView("_UserSignUp", signupModel);
 

Login Partial View (Validation Error Display Not Working)

@model Inshora.Models.Account.LoginViewModel

<div asp-validation-summary="ModelOnly" class="text-danger"></div>

<div class="panel-heading">
 <h3 class="panel-title">Log Into Your Account</h3>
</div>
<div class="panel-body">
 <div class="row">
 <div class="col-xs-12">
 <form id="login-form" asp-controller="Account" asp-action="Login" method="post" role="form" style="display: block;"
 data-ajax="true" data-ajax-method="POST" data-ajax-mode="replace" data-ajax-update="formData" data-ajax-complete="AcctLib.Login.Events.onComplete">
 @Html.AntiForgeryToken()
 <div class="form-group">
 <input type="text" name="UserName" id="UserName" tabindex="1" class="form-control" placeholder="Email Address" value="@Model.UserName">
 <span asp-validation-for="UserName" class="text-danger"></span>
 </div>
 <div class="form-group">
 <input type="password" name="Password" id="Password" tabindex="2" class="form-control" placeholder="Password">
 <span asp-validation-for="Password" class="text-danger"></span>
 </div>
 <div class="form-group text-center">
 <input type="checkbox" tabindex="3" class="" name="RememberMe" id="RememberMe">
 <label for="RememberMe"> Remember Me</label>
 </div>
 <div class="form-group">
 <div class="row">
 <div class="col-sm-6 col-sm-offset-3">
 <input type="submit" name="login-submit" id="login-submit" tabindex="4" class="form-control btn btn-primary" value="Log In">
 </div>
 </div>
 </div>
 <div class="form-group">
 <div class="row">
 <div class="col-lg-12">
 <div class="text-center">
 <a id="PasswordReset" asp-controller="Account" asp-action="PasswordReset" data-ajax="true" data-ajax-method="GET" data-ajax-mode="replace" data-ajax-update="#formData" tabindex="5" class="inshora-forgot-password">Forgot Password?</a>
 </div>
 </div>
 </div>
 </div>
 </form>
 </div>
 </div>
</div>

<script type="text/javascript">
 $(document).ready(function() 
 AcctLib.Login.Init();
 )
</script>

LoginViewModel

public class LoginViewModel

 [Required]
 public string UserName get; set; 

 [Required]
 public string Password get; set; 

 [Required]
 public bool RememberMe get; set; 

Client Side Initialization Code

AcctLib.Login.RebindForm = function() 
 $('form').each(function (i, f) 
 $form = $(f);
 $form.removeData('validator');
 $form.removeData('unobtrusiveValidation');
 $.validator.unobtrusive.parse($form);
 );


AcctLib.Login.Init = function () 
 AcctLib.Login.RebindForm();
 $('#UserName').focus();

Update

I have updated the parent page (index.cshtml) to the following and it still doesn't display the messages.

<div class="row">
 <div class="col-sm-8 col-sm-offset-2">
 <div class="panel panel-primary" id="formData">
 @await Html.PartialAsync("_UserNamePartial", new UserNameViewModel())
 </div>
 </div>
</div>

@section Scripts

 @ await Html.RenderPartialAsync("_ValidationScriptsPartial"); 

The problem was that I had not used the asp-for tag helpers. Those helpers are responsible for generating the data-* attributes needed by the unobtrusive validation parser. Once I started using them it started working. Thank you to everyone who tried to help.

Corrected View

<div class="panel-body">
 <div class="row">
 <div class="col-xs-12">
 <form id="login-form" asp-controller="Account" asp-action="Login" method="post" role="form"
 data-ajax="true" data-ajax-method="POST" data-ajax-mode="replace" data-ajax-update="#formData">
 @Html.AntiForgeryToken()
 <div asp-validation-summary="ModelOnly" class="text-danger"></div>
 <div class="form-group">
 <label asp-for="UserName"></label>
 <input asp-for="UserName" class="form-control" placeholder="Email Address"/>
 <span asp-validation-for="UserName" class="text-danger"></span>
 </div>
 <div class="form-group">
 <label asp-for="Password"></label>
 <input asp-for="Password" class="form-control" placeholder="Password"/>
 <span asp-validation-for="Password" class="text-danger"></span>
 </div>
 <div class="form-group text-center">
 <input asp-for="RememberMe" />
 <label asp-for="RememberMe"> Remember Me</label>
 </div>
 <div class="form-group">
 <div class="row">
 <div class="col-sm-6 col-sm-offset-3">
 <input type="submit" name="login-submit" id="login-submit" tabindex="4" class="form-control btn btn-primary" value="Log In">
 </div>
 </div>
 </div>
 <div class="form-group">
 <div class="row">
 <div class="col-lg-12">
 <div class="text-center">
 <a id="PasswordReset" asp-controller="Account" asp-action="PasswordReset" data-ajax="true" data-ajax-method="GET" data-ajax-mode="replace" data-ajax-update="#formData" tabindex="5" class="inshora-forgot-password">Forgot Password?</a>
 </div>
 </div>
 </div>
 </div>
 </form>
 </div>
 </div>
</div>

if (!ModelState.IsValid)
 return PartialView("..\Home\_UserNamePartial", model);

pretty sure this violates pathing

if(!ModelState.IsValid)
 return PartialView("../Home/_UserNamePartial", model);