CODEWITHSUNDEEP
asp.netasp.net-mvchttp-postviewmodel
Kaffeepause
Kaffeepause

Reputation: 228

ASP.NET MVC objects lost on post method

I just came across this topic in a current project and I would like to know the best way to handle the "problem" of objects getting lost, when using the HttpPost method when submitting a form. Thoughout the web and the posts on stackoverflow I gathered some ways to deal with it.

So, once I got that a view model gets objects or lists from the HttpGet request they are lost because of the stateless nature of http. I now have seen different approaches to get that objects back when passing the view model back to the view.

Store objects in hidden field

@Html.HiddenFor(m => m.Object)

This seems to be working fine if the view models property is serializable. But what if there is logic behind the objects? Will this work for all scenarios? And on the other hand, I don't want every object inside my view model, just the ones for display and the user can interact with.

Get the object via AJAX and HelperMethods

@Html.Some3rdParty().ComboBoxFor(m => m.List)
    .DataSourceUrl(@Url.Action("GetComboSource"))

[ComboBoxSource]
public ActionResult GetComboSource()
{
    var data = Service.GetStaticSource();

    return Json(data);
}

Using 3rd party libraries like Kendo UI MVC I can easily put a .DataSourceUrl() HtmlHelper on my control for requesting a controller to provide the datasource. Or just using jQuery's $.get() method. The problem is: What if I can't use such a library or the requirement says, that JS has to be avoided as much as possible?

Get the object back in the HttpPost Controller action

[HttpPost]
public ActionResult Edit(ViewModel viewModel)
{
    var tempViewModel = Service.GetViewModel(viewModel.Id);
    viewModel.Object = tempViewModel.Object;

    return View(viewModel);
}

This one seems a bit brittle to me. On the post action I have to call whatever service provides the view model, extract certain objects and attach them to my recieved view model.

Currently that's all I can think of, but in short:

I'd like to know, what is the best practise to handle it throughout a project and what's the best way for maintainability?

For me it seems there is no perfect solution so far. How do you do it in your projects?

Upvotes: 2

Views: 2950

Answers (2)

Caner Tezcan
Caner Tezcan

Reputation: 166

Just change 

<input class="ui-input-text " type="text" id="PlateNo" tabindex="2" name="PlateNo">

to

<input class="ui-input-text " type="text" id="PlateNo" tabindex="2" name="PlateNo" value="@Request["PlateNo"]">

You can be show on the textbox sending value for this input. Only add value="@Request["yourinputname"] to your input.

Upvotes: 0

Gregoire
Gregoire

Reputation: 24832

Avoid solution 1: you will weigh your requests, the data can be forged and if your object is not serializable (or the to string method does not provide useful string) you will have some problems. If you want to use something similar prefer Session

Solution 2: I use ajax populating when the input have to be filtered depending of other controls value. If it is not the case you will have controller with lot of actions and not easily maintanable.

Solution 3 is the one I use and I prefer because it is more DRY, more secure (no forgery), and keeps the controller light.

Upvotes: 2

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