I mentioned on the comments I was having the same issue but later today I figured at MSDN that this is an expected behaviour if you are returning the same model and view types after a POST. For my scenario I had to use ModelState.Clear() before changing any values on the returning view model. To explain a little better, I'll try to describe my case as close as I can remember to try to contextualize:
view models
// ~/Models/SomeFeatureModels.cs
public class SomeViewModel {
public int Id {get;set;}
public string SomeField{get;set;}
public string SomeOtherField{get;set;}
public DateTime CreatedOn{get;set;}
}
public class SomeOtherViewModel {
public int Id {get;set;}
public string SomeField{get;set;}
public string SomeOtherField{get;set;}
public DateTime CreatedOn{get;set;}
}
public class IndexViewModel {
public string FeatureTitle{get;set;}
}
templates
<!-- ~/Views/Some/SomeInfo.cshtml -->
@model.App.Models.SomeInfoViewModel
@using(Html.BeginForm("AddSomeInfo", "Some", FormMethod.Post, new { @id="frmAddSomeInfo" }) {
<div id="some-info">
@Html.DisplayFor(m=>m.SomeField)
@Html.EditorFor(m=>m.SomeField)
@Html.ValidatorFor...
<input type="submit">Go</input>
</div>
}
<!-- ~/Views/Some/SomeInfo.cshtml -->
@model.App.Models.SomeOtherInfoViewModel
@using(Html.BeginForm("AddSomeOtherInfo", "Some", FormMethod.Post, new { @id="frmAddSomeOtherInfo" }) {
<div id="some-other-info">
@Html.DisplayFor(m=>m.SomeField)
@Html.EditorFor(m=>m.SomeField)
@Html.ValidatorFor...
<input type="submit">Go</input>
</div>
}
<!-- ~/Views/Some/Index.cshtml -->
@model App.Models.IndexViewModel
@{
layout: "someLayout.cshtml"
}
<h2>Model.FeatureTitle</h2>
@{ RenderAction("SomeInfo") }
@{ RenderAction("SomeOtherInfo") }
@section scripts {
//bundle must include:
// jquery, jquery.unobtrusive.ajax, jquery.validate, jquery.validate.unobtrusive
<script>
$(function() {
$('#frmAddSomeInfo').submit(function(e) {
e.preventDefault();
var form = $(this);
if (form.valid()) {
$.ajax({
url: form.action,
type: form.method,
data: form.serialize()
}).done(function(payload) {
$('#some-info').html(payload);
}).fail(function(jqXHR, error, errorThrown) {
// handle
});
}
});
$('#frmAddSomeOtherInfo').submit(function(e) {
e.preventDefault();
var form = $(this);
if (form.valid()) {
$.ajax({
url: form.action,
type: form.method,
data: form.serialize()
}).done(function(payload) {
$('#some-other-info').html(payload);
}).fail(function(jqXHR, error, errorThrown) {
// handle
});
}
});
});
</script>
}
controller
// ~/Controllers/SomeController.cs
public class SomeController: Controller {
// This would be the landing view of a given controller
public ActionResult Index() {
// for this view model I have basically typed the things that
// are a concern of Index, like page title and other things
// but nothing related to the view models that I will be
// updating or inserting
var viewModel = somePrivateMethodToBuildMyViewModel();
return View(viewModel);
}
public PartialViewResult SomeInfo() {
// this is technically a fresh instance with normalized
// or localized default data that I will be sending
// when the index requests this partial view
var someViewModel = somePrivateMethodToBuildSomeViewModel();
return PartialView(someViewModel);
}
[HttpPost]
public PartialViewResult AddSomeInfo(SomeViewModel viewModel) {
// this is where I am checking if my view model is alright
// and then the "issue" will occur
if (!ModelState.IsValid) {
// ... handle
} else {
// I was doing "normal stuff" like
// translating view model to an entity (let's call it model)
// committing changes with some ORM and get and id and timestamp back
// and naturally assign these values to the view model
viewModel.Id = model.id;
viewModel.createdOn = model.created_on;
}
// then return the same view and same model **types** of the request
return PartialView("SomeInfo", viewModel);
}
}
This is the part that I had to use ModelState.Clear(). I've changed my POST action to this:
// ~/Controllers/SomeController.cs
public class SomeController: Controller {
// ...
[HttpPost]
public PartialViewResult AddSomeInfo(SomeViewModel viewModel) {
if (!ModelState.IsValid) {
// ... handle
} else {
// Included this line for valid model state handling
ModelState.Clear();
// then persist, etc
// then change view model
viewModel.Id = model.id;
viewModel.createdOn = model.created_on;
}
// then returning the view model to the same partial should now work
return PartialView("SomeInfo", viewModel);
}
}
Sorry this got a little too much, but I just wanted to show how I got it working on my scenario.
