CODEWITHSUNDEEP
c#asp.netasp.net-mvc
Justin
Justin

Reputation: 472

Persist Data through multiple form POSTs

I was wondering what the best way to approach this problem in ASP.NET MVC would be. The following is a trivial example of what I'd like to be able to do:

I have a webpage with textbox and a submit button. When the submit button is pressed the I would like the contents to be displayed on the same webpage. When it is pressed again I would like what was already displayed from the first submission to be displayed as well as the new data that was just submitted.

I have tried saving this data to a model, but the model is wiped clean every time the form posts. How could I do this and keep the data from the post before the last one (and the post before that)?

Upvotes: 3

Views: 1609

Answers (2)

Diego Garcia
Diego Garcia

Reputation: 1144

Just put an hidden field for your model property then your previews value will be loaded on it and passed it back to the next post.

Ex.: @Html.HiddenFor(model => model.YourProperty)

So knowing that you could have two properties ex.: one named newValue and other called allValues.

the allValues you use it with an hidden field and your newValue you use to insert the new ones. So on post you just add the newValue to the allValues.

Something like that: model.allValues += newValue;

--UPDATE

Or you can use session or tempdata as mentioned by @Jesse

For this case I would prefer to use hidden fields as it has a lower complexity and its data didnt need be secure as it will be shown to the user anyway.

Upvotes: 1

Jesse
Jesse

Reputation: 8393

If you want data to persist between requests, as a starting point I would use 'TempData'. The TempData property value is stored in session state and exists until it is read or until the Session expires.

Example ViewModel:

    public class SomeClass
    {
        public string Something { get; set; }
        public List<string> RetainedValues { get; set; } 
    }

Example Controller:

    [HttpGet]
    public ActionResult Index()
    {
        return View("Index");
    }

    [HttpPost]
    public ActionResult Index(SomeClass postedValues)
    {
        // retrieve retained values
        var retained = (List<string>) TempData["RetainedValues"] ?? new List<string>();
        retained.Add(postedValues.Something);

        // save for next post
        TempData["RetainedValues"] = retained;

        // setup viewmodel
        var model = new SomeClass
        {
            RetainedValues = retained
        };

        return View("Index", model);
    }

Example View (strongly typed):

    <div>
        @foreach(var item in Model.RetainedValues)
        {
            <div>@item</div>
        }
    </div>
    @using(Html.BeginForm())
    {
        @Html.EditorFor(m=>m.Something)
        <input type="submit"/>
    }

Upvotes: 3

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