View is posting a empty object on submit when expecting the modified object - asp.net-core

Question

I have a View that lets users edit data that is fetched from a database and converted into a DataTable (for simplicity since the data can get really complicated and deep).
The issue is that when I POST the data back to the responsible Controller the controller receives the DataTable object but it's empty, e.g. the changes made by a user never get back to the Controller and cannot be saved to Database.
I am at most intermediate at web programming so I appreciate straight answers or direct pointers.
View:
#model System.Data.DataTable
#{
ViewData["Title"] = "Edit";
Layout = "~/Views/Shared/_LayoutAdminlte.cshtml";
}
#using (Html.BeginForm("EditSave", "Recipe", FormMethod.Post, new { #id = "Properties-Form" }))
{
#Html.AntiForgeryToken()
<div class="form-horizontal">
#Html.ValidationSummary(true, "", new { #class = "text-danger" })
<div class="form-group">
<h2>#Html.DisplayFor(m => Model.TableName)</h2>
</div>
<div class="box box-primary">
<table id="Properties" class="table table-condensed">
<thead>
<tr>
#foreach (System.Data.DataColumn col in Model.Columns)
{
<th>
#Html.DisplayFor(m => col.Caption)
</th>
}
</tr>
</thead>
<tbody>
#foreach (System.Data.DataRow row in Model.Rows)
{
<tr>
#foreach (var cell in row.ItemArray)
{
<td>
#if (row.ItemArray.ToList().IndexOf(cell) == 0)
{
#cell.ToString()
}
else
{
<input asp-for="#cell" />
}
</td>
}
</tr>
}
</tbody>
</table>
</div>
<div class="box-footer">
<!-- id="Save" -->
<input class="btn btn-primary pull-right" type="submit" value="Spara" id="Save" />
<i class="fa fa-show"></i> Visa
<i class="fa fa-show"></i> Avbryt
</div>
</div>
}
#section Scripts{
#await Html.PartialAsync("_ValidationScriptsPartial")
}
Controller:
[HttpPost]
public ActionResult EditSave(DataTable model)
{
Debugger.Break();
return View("Edit", model);
}

Answer 1

This <input asp-for="#cell" /> is your problem.
If you run your program and use the developer tools to inspect the html generated for the input fields, you will notice the generated html attributes.
the particular one that you should pay attention to is the name attribute.
The way model binding works in .net core when you send data to the controller.
public IActionResult DoSomething(Model model) { ... }
you would have match the name attribute to the property of the object. Example:
<input name="model.Level" value="8999" />
so then you would get var level = model.Level and level will be 8999.
So you have to take care when you use the asp-for it's not doing as much heavy lifting as you think. Always check the html generated.
PS
Don't use DataTables, other developers will throw rocks at you. Don't be lazy map to an actual object or use an ORM, programs quickly become unmaintainable if you use them to dynamically store data.