Read a Static Json File and View it as table in ASP .Net Core

Question

I am trying to read a .json File and return the value as a table in asp .net Core 3.1! I am new at working with asp .net core, so please help me from a beginners perspective.

Consider the code snippet below. My problem is that I cannot pass the values from the controller to the view.

I encounter this exception:

An unhandled exception occurred while processing the request.
InvalidOperationException: The model item passed into the ViewDataDictionary is of type '.Sample.Models.Mstype', but this ViewDataDictionary instance requires a model item of type 'Sample.Models.Mstypes'.

Controller

  public IActionResult Run()
        {
            ...

            var webClient = new WebClient();
            var json = webClient.DownloadString(@"/app/results/type.json");
            var mstypes = JsonConvert.DeserializeObject<Mstype>(json);
            
            return View(mstypes);

        }

Mstype.cs

  public int CIS { get; set; }
        public int PPMS { get; set; }
        public int RRMS { get; set; }
        public int SPMS { get; set; }
        public int not_sure { get; set; }

Mstypes.cs

 public class Mstypes
    {
        public IList<Mstype> mstypes { get; set; }
    }

View

@model Fed_PiP.Models.Mstypes

@{
    ViewData["Title"] = "Run";
}


<table class="table">

    <thead>
        <tr>
            <th>
                @Html.DisplayNameFor(Model => Model.mstypes[0].CIS)
            </th>
            <th>
                @Html.DisplayNameFor(Model => Model.mstypes[0].PPMS)

            </th>
            <th>
                @Html.DisplayNameFor(Model => Model.mstypes[0].RRMS)

            </th>
            <th>
                @Html.DisplayNameFor(Model => Model.mstypes[0].SPMS)

            </th>
            <th>
                @Html.DisplayNameFor(Model => Model.mstypes[0].not_sure)

            </th>
            <th></th>
        </tr>
    </thead>
    <tbody>

       
            <tr>
                <td>
                    @Model.mstypes.FirstOrDefault().CIS
                </td>
                <td>
                    @Model.mstypes.FirstOrDefault().PPMS
                </td>
                <td>
                    @Model.mstypes.FirstOrDefault().RRMS
                </td>
                <td>
                    @Model.mstypes.FirstOrDefault().SPMS
                </td>
                <td>
                    @Model.mstypes.FirstOrDefault().not_sure
                </td>
            </tr>

    </tbody>
</table>

and finally json file

{"CIS":11,"PPMS":12,"RRMS":6,"SPMS":11,"not_sure":10}

also, I have a question is there any way to make a dynamic table from the static JSON files? I mean without defining the model or ViewModel just reading and returning the values from the static file to the tables?

What's the model type declared in the view? I think you should do JsonConvert.DeserializeObject<Mstypes>(json) — Chetan
– Chetan, Commented Sep 15, 2020 at 20:07

mj1313 · Accepted Answer · 2020-09-16 03:27:50Z

1

It is very clear from the error message, the view accept a Mstypes type model, while you pass a Mstype to it.

So, you can encapsulate mstypes convert it to Mstypes type in your controller.

public IActionResult Run()
{
    var json = "{ 'CIS':11,'PPMS':12,'RRMS':6,'SPMS':11,'not_sure':10}";
    var mstype1 = JsonConvert.DeserializeObject<Mstype>(json);
    Mstypes mstypes = new Mstypes
    {
        mstypes = new List<Mstype> { mstype1 }
    };

    return View(mstypes);
}

Result:

answered Sep 16, 2020 at 3:27

mj1313

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1 Comment

Ashkan Pirmani Over a year ago

Great, Works! Thank you!

Frank Nielsen · Accepted Answer · 2020-09-15 20:26:25Z

1

What if you change:

var mstypes = JsonConvert.DeserializeObject<Mstype>(json);

to

var mstypes = JsonConvert.DeserializeObject<Mstypes>(json);

Your .json file should be something like:

{
  mstypes : [
    {"CIS":11,"PPMS":12,"RRMS":6,"SPMS":11,"not_sure":10},
    {"CIS":11,"PPMS":12,"RRMS":6,"SPMS":11,"not_sure":10},
    {"CIS":11,"PPMS":12,"RRMS":6,"SPMS":11,"not_sure":10},
    {"CIS":11,"PPMS":12,"RRMS":6,"SPMS":11,"not_sure":10},
    {"CIS":11,"PPMS":12,"RRMS":6,"SPMS":11,"not_sure":10},
  ]
}

edited Sep 15, 2020 at 20:26

answered Sep 15, 2020 at 20:09

Frank Nielsen

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4 Comments

Ashkan Pirmani Over a year ago

Thank you! But it returned Null Value! <ArgumentNullException: Value cannot be null. (Parameter 'source') >

Frank Nielsen Over a year ago

Your json file do not reflect the schema you want, and use in your View

Ashkan Pirmani Over a year ago

what it should be?

ESG Over a year ago

To match the json above, the type should be Mstype[] for both the @Model line and the call to DeserializeObject

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