Html Helper to get values from Model State - asp.net-mvc

Question

Asp.Net MVC 3
I seem to have a similar problem as this post answered by Darin Dimitrov. So, Darin if you are reading this, please help :)
asp.net-mvc2 - Strongly typed helpers not using Model?
The problem I have is I am looking for an html helper that will contain the posted value in the modelstate.
For example, if I use an editor for like this:
#Html.EditorFor(model => model.SelectedTags)
I can see the value that was posted. The problem is I need a way to get this value without creating a textbox, I just want the string because I need it in some javascript.
I've tried DisplayFor, but that doesn't contain the posted value:
#Html.DisplayFor(model => model.SelectedTags)
By the way, I don't find this behavior intuitive AT ALL. I spent a few hours debugging ModelStateToTempDataAttribute from MVCContrib thinking it was a bug in their code to Import/Export Model State.
Thanks for any help!
Edit - Added Repro Code
Take these steps to reproduce:
Start project. Property1 should be blank (required), Property2 should have "abc"
Change Property2 to "xxx"
Submit Form (notice ClientValidationEnabled is False)
Form is posted, redirect, load (PRG). Property2 textbox has"xxx" and right below you will see "abc" from DisplayFor.
Controller
[ModelStateToTempData] //From MVCContrib
public class HomeController : Controller
{
[HttpGet]
public ActionResult Index()
{
//simulate load from db
var model = new FormModel() { MyProperty2 = "abc" };
return View(model);
}
[HttpGet]
public ActionResult Success()
{
return View();
}
[HttpPost]
public ActionResult Index(FormModel model)
{
if (ModelState.IsValid)
{
return RedirectToAction("Success");
}
else
{
return RedirectToAction("Index");
}
}
}
Model
public class FormModel
{
[Required]
public string MyProperty1 { get; set; }
public string MyProperty2 { get; set; }
}
View
#model MvcApplication4.Models.FormModel
#using (Html.BeginForm()) {
#Html.ValidationSummary(true)
<fieldset>
<legend>FormModel</legend>
<div class="editor-label">
#Html.LabelFor(model => model.MyProperty1)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.MyProperty1)
#Html.ValidationMessageFor(model => model.MyProperty1)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.MyProperty2)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.MyProperty2)
#Html.ValidationMessageFor(model => model.MyProperty2)
</div>
#Html.DisplayFor(model => model.MyProperty2)
<p>
<input type="submit" value="Save" />
</p>
</fieldset>
}
Config:
<add key="ClientValidationEnabled" value="false" />
ModelStateToTempData (MVCContrib):
public class ModelStateToTempDataAttribute : ActionFilterAttribute
{
public const string TempDataKey = "__MvcContrib_ValidationFailures__";
/// <summary>
/// When a RedirectToRouteResult is returned from an action, anything in the ViewData.ModelState dictionary will be copied into TempData.
/// When a ViewResultBase is returned from an action, any ModelState entries that were previously copied to TempData will be copied back to the ModelState dictionary.
/// </summary>
/// <param name="filterContext"></param>
public override void OnActionExecuted(ActionExecutedContext filterContext)
{
var modelState = filterContext.Controller.ViewData.ModelState;
var controller = filterContext.Controller;
if(filterContext.Result is ViewResultBase)
{
//If there are failures in tempdata, copy them to the modelstate
CopyTempDataToModelState(controller.ViewData.ModelState, controller.TempData);
return;
}
//If we're redirecting and there are errors, put them in tempdata instead (so they can later be copied back to modelstate)
if((filterContext.Result is RedirectToRouteResult || filterContext.Result is RedirectResult) && !modelState.IsValid)
{
CopyModelStateToTempData(controller.ViewData.ModelState, controller.TempData);
}
}
private void CopyTempDataToModelState(ModelStateDictionary modelState, TempDataDictionary tempData)
{
if(!tempData.ContainsKey(TempDataKey)) return;
var fromTempData = tempData[TempDataKey] as ModelStateDictionary;
if(fromTempData == null) return;
foreach(var pair in fromTempData)
{
if (modelState.ContainsKey(pair.Key))
{
modelState[pair.Key].Value = pair.Value.Value;
foreach(var error in pair.Value.Errors)
{
modelState[pair.Key].Errors.Add(error);
}
}
else
{
modelState.Add(pair.Key, pair.Value);
}
}
}
private static void CopyModelStateToTempData(ModelStateDictionary modelState, TempDataDictionary tempData)
{
tempData[TempDataKey] = modelState;
}
}

Answer 1

you can read these values from modelstate dictionary like
<%:Html.ViewData.ModelState["key"] %>
However, it seems to me that SelectedTags is an enumeration of objects that is displayed for editing when you call EditorFor(model=>model.SelectedTags). in this scenario it is highly unlikely that you get anything by calling Html.ViewData.ModelState["SelectedTags"]. you will have to iterate over the keys in ModelState dictionary instead and check if key begins with SelectedTags prefix and then u can read its value accordinly.

Answer 2

In your Views -> Shared -> DisplayTemplates, create SelectedTags.cshtml
This will be your display template. Inside write something on the lines of
#model YourProject.WebUI.Models.SelectedTags
#for(int i = 0; i < Model.Tags.Count(); i++){
// Assuming that selected tags contains a list of tags.
// Replace <p> with whatever feels suitable
<p>Model.Tags[i]</p>
}
You can then use this display template in your views:
#Html.DisplayFor(model => model.SelectedTags,"SelectedTags")
This should also work:
#Html.DisplayFor(model => model.SelectedTags)