Show List string in HTML(MVC) using loop

Question

I am trying to show a List<string> in my HTML using a loop. I get the following output:

System.Collections.Generic.List`1[System.String]

I have seen this before, but not in the way I am currently coding: I tried 2 loops for showing the values in that List<string> but both of them return the same above mentioned result:

HTML

@{
    Layout = "~/Administration/Views/Shared/_AdminLayout.cshtml";
}
@using Telerik.Web.Mvc.UI
@using Nop.Plugin.Misc.ExportAttributes.Models;
@model ImportCalculationSheetModel
@using Nop.Web.Framework;
@using (Html.BeginForm())
{
   <ul>
      @for (int i = 0; i < Model.FailedProductIdsList.Count; i++)
      {
          <li><b>@Convert.ToString(Model.FailedProductIdsList[i])</b></li>
      }
   </ul>
}

For loop:

<ul>
   @for (int i = 0; i < Model.FailedProductIdsList.Count; i++)
   {
      <li><b>@Convert.ToString(Model.FailedProductIdsList[i])</b></li>
   }
</ul>

Foreach loop:

<ul>
   @foreach(var productId in Model.FailedProductIdsList)
   {
      <li><b>@Convert.ToString(productId);</b></li>
   }
</ul>

When debugging I see that only one value is inserted in the List<string>: "99999" So it isn't even necessary converting to string, but I did it just to be sure, since the result is the same when not converting.

The model I am using: ImportCalculationSheetModel is referenced in View using @model ImportCalculationSheetModel

Model

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Nop.Web.Framework;
using Nop.Web.Framework.Mvc;

namespace Nop.Plugin.Misc.ExportAttributes.Models
{
    public class ImportCalculationSheetModel : BaseNopModel
    {
        public List<string> FailedProductIdsList { get; set; }
    }
}

So my Model is only filled with 1 List<string>, the list gets filled in my Controller.

Controller

[HttpGet]
public ActionResult ImportCalculationSheetSucceededWithFailures(ImportCalculationSheetModel model)
{
   return View("Nop.Plugin.Misc.ExportAttributes.Views.MiscExportAttributes.ImportCalculationSheetSucceededWithFailures", model);
}

[HttpPost]
public ActionResult ImportCalculationSheet(ImportCalculationSheetModel model)
{
    if (ModelState.IsValid)
    {
           ImportFromCalculationSheet _importFromCalculationSheet = new      ImportFromCalculationSheet();
           var file = Request.Files["importexcelfile"];
           if (file != null && file.ContentLength > 0)
           {
              _importFromCalculationSheet.ImportProductsFromXlsx(file.InputStream);
              model.FailedProductIdsList = _importFromCalculationSheet.FailedToUpdateIds;
           }
           else
           {
             return RedirectToAction("ImportCalculationSheet", model);
           }
           if (model.FailedProductIdsList.Count > 0)
           {
             return RedirectToAction("ImportCalculationSheetSucceededWithFailures", model);
           }
           else
           {
             return RedirectToAction("ImportCalculationSheetSucceeded", model);
           }
   }
   else
   {
       return RedirectToAction("ImportCalculationSheet", model);
   }
}

FailedProductIdsList gets filled at following line:

model.FailedProductIdsList = _importFromCalculationSheet.FailedToUpdateIds;

I can see that it doesn't fail there, when debugging.

Question

Why are the for loop and foreach loop returning:

System.Collections.Generic.List`1[System.String]

When I only grab one item in the List<string> at a time and even convert it to a string? Is there a way to debug this problem better in the view?(Breakpoints in the View aren't hit)

FailedProductIdsList is already a list of strings so no need to convert it to a string again inside your loops. — Sam Leach
– Sam Leach, Commented Oct 8, 2013 at 9:57
See this - stackoverflow.com/questions/17469697/… .It seems that maybe `Convert.ToString()`` is causing all the problems. — Leron
– Leron, Commented Oct 8, 2013 at 10:52
You said there is no errors in "model.FailedProductIdsList = _importFromCalculationSheet.FailedToUpdateIds;" I doubt this is the problem. But can you please check the actual type that the list get assigned to. Also try doing _importFromCalculationSheet.FailedToUpdateIds.ToList(); — Spock
– Spock, Commented Oct 8, 2013 at 11:04
@Raj I have checked it, but it is giving me the same result. — Max
– Max, Commented Oct 8, 2013 at 11:11
You said the breakpoint does not hit on the View page. Perhaps you are referencing to an older version of the page? I suggest close the VS and delete all your ASP.NET temporary files and start the app again. If that doesn't solve the problem, try to replicate your issue in a Sample MVC app. Make sure you have the same set-up except any other additional dependencies. Good luck. — Spock
– Spock, Commented Oct 8, 2013 at 12:12

Sam Leach · Accepted Answer · 2013-10-08 10:43:25Z

4

Use the foreach:

No need to convert to string as FailedProductIdsList is already a list of strings.

<ul>
   @foreach(var productId in Model.FailedProductIdsList)
   {
      <li><b>@productId</b></li>
   }
</ul>

EDIT:

Simplify your controller to:

[HttpPost]
public ActionResult ImportCalculationSheet(ImportCalculationSheetModel model)
{
    var m = new ImportCalculationSheetModel { 
        FailedProductIdsList = new List<string> { "test1", "test2", "test3" } 
    };

    if (ModelState.IsValid)
    {
        return View("ViewName", m);
    }
}

does that print the list?

edited Oct 8, 2013 at 10:43

answered Oct 8, 2013 at 9:58

Sam Leach

13k10 gold badges49 silver badges73 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Max Over a year ago

This is the sort of the foreach loop I showed in my question, I already tried this, with and without Converting to String

Sam Leach Over a year ago

Then the list is empty. What is the problem?

Max Over a year ago

Maybe the Model doesn't send correctly to the view, but the list is set and the first value is filled as said in question. So it should at least print the "99999" as mentioned in question.

Max Over a year ago

Using the controller you provided me returns the same: System.Collections.Generic.List`1[System.String]

Max · Accepted Answer · 2013-10-17 06:39:43Z

1

I found and fixed the problem:

I am redirecting to an action in my code, what I shouldn't do, because the model will be cleared then.

So instead of following code:

if (model.FailedProductIdsList.Count > 0)
{
   return RedirectToAction("ImportCalculationSheetSucceededWithFailures", model);
}

I now use following code:

if (model.FailedProductIdsList.Count > 0)
{
   return View("Nop.Plugin.Misc.ExportAttributes.Views.MiscExportAttributes.ImportCalculationSheetSucceededWithFailures", model);
}

The difference is that I am not calling that other method which creates a new clean model, but I send the model directly to the View this way.

answered Oct 17, 2013 at 6:39

Max

13.5k16 gold badges78 silver badges105 bronze badges

2 Comments

Spock Over a year ago

Great you found the answer. You said "The difference is that I am not calling that other method which creates a new clean model" In this mean your below Get Action? [HttpGet] public ActionResult ImportCalculationSheetSucceededWithFailures(ImportCalculationSheetModel model) { Were you creating a new clean model here before sending it to the View? Or you are talking about something else?

Max Over a year ago

RedirectToAction, did redirect me to a [HttpGet] method, that created a new model, so the list is always empty. I'm now sending the filled model to the View, without creating a new model, as seen in my code above.

Collectives™ on Stack Overflow

Show List string in HTML(MVC) using loop

2 Answers 2

4 Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related