Styling Data Validation Errors with Bootstrap - asp.net-mvc-4

Question

I am working on an ASP.NET MVC 4 Project. I want to style data validation errors on my login page with Bootstrap 3.0. When I debug the page and it gives data validation errors, this codes are disappeared in source of my login form:
<form action="/Account/Login" class="col-md-4 col-md-offset-4 form-horizontal well" method="post"><input name="__RequestVerificationToken" type="hidden" value="Zbg4kEVwyQf87IWj_L4alhiHBIpoWRCJ9mRWXF6syGH4ehg9idjJCqRrQTMGjONnywMGJhMFmGCQWWvBbMdmGFSUPqXpx6XaS4YfpnbFm8U1" /><div class="validation-summary-errors"><ul><li>The user name or password provided is incorrect.</li>
</ul></div> <div class="form-group control-group">
<div class="col-md-6 col-md-offset-3">
<input class="input-validation-error form-control" data-val="true" data-val-required="User name alanı gereklidir." id="UserName" name="UserName" placeholder="Kullanıcı Adı" type="text" value="" />
<span class="field-validation-error" data-valmsg-for="UserName" data-valmsg-replace="true">User name alanı gereklidir.</span>
</div>
</div>
<div class="form-group">
<div class="col-md-6 col-md-offset-3">
<input class="input-validation-error form-control" data-val="true" data-val-required="Password alanı gereklidir." id="Password" name="Password" placeholder="Şifre" type="password" />
<span class="field-validation-error" data-valmsg-for="Password" data-valmsg-replace="true">Password alanı gereklidir.</span>
</div>
</div>
<div class="form-group">
<div class="col-md-4 col-md-offset-4">
<button class="btn btn-default" type="submit">Giriş Yap</button>
</div>
</div>
</form>
How can I style these errors like "for=inputError" property of label with Bootstrap 3?

Answer 1

As it's shown in Bootstrap's docs, you need to apply class has-error to the div that contains the input and has class form-group:
<div class="form-group has-error">
...
</div>
It's a quite ugly to write a condition for each property you want to check and apply class has-error depending on the results of that condition, though you can do it like so:
<div class="form-group #(Html.ViewData.ModelState.IsValidField(Html.IdFor(x => x.UserName)) ? null : "has-error" )">
This takes care of the server side validation. However, there is also client side validation you need to think about. For that you'd need to write some jQuery that would check for existence of class field-validation-error and apply class has-error depending on the result.
You may do it all your self, though I suggest checking out TwitterBootstrapMVC which does all of that automatically for you. All you'd have to write is:
#Html.Bootstrap().FormGroup().TextBoxFor(m => m.UserName)
Disclaimer: I'm the author of TwitterBootstrapMVC. Using it in Bootstrap 2 is free. For Bootstrap 3 it requires a paid license.