I want use foreach for list in C# in controller Create([FromBody] CardList cards). I get the error Type 'WordStudy.Models.CardList' can only be used in 'foreach' statements if it implements 'IEnumerable' or 'IEnumerable', or if it has a suitable 'GetEnumerator' method whose return type has a 'Current' property and a 'MoveNext' method. When I implemented IEnumerable in my class it gets null.
script.js
ar currentCardNumber = 1;
function addCard() {
currentCardNumber++;
let newCardHTML = `
<div class="header d-flex justify-content-between p-3">
<h4 class="card-counter">${currentCardNumber}</h4>
</div>
<div class="card-body row">
<div class="term col">
<h3>Term</h3>
<input class="form-control w-100" name = "term" >
</div>
<div class="definition col">
<h3>Definition </h3>
<input class="form-control w-100" name="definition" >
</div>
</div>
</div> `;
let newCard = document.createElement('div');
newCard.classList.add('card');
newCard.classList.add('mt-3');
newCard.innerHTML = newCardHTML;
let addNewCard = document.querySelector('.cards');
let referenceNode = document.getElementById('create-cards');
addNewCard.insertBefore(newCard, referenceNode);
}
function saveCardDataToServer() {
let cards = [];
document.querySelectorAll('.cards > .card ').forEach((card) => {
let termInput = card.querySelector('input[name="term"]');
let definitionInput = card.querySelector('input[name="definition"]');
if (termInput && definitionInput) {
let term = termInput.value.trim();
let definition = definitionInput.value.trim();
cards.push({
Term: term,
Definition: definition
});
}
else {
console.error("Input elements not found in card:", card);
}
})
fetch('/Cards/Create/', {
method: 'POST',
headers: {
'Content-Type': 'application/json'
},
body: JSON.stringify({Cards: cards})
})
.then(response => response.json())
.then((data => {
if (data.success) {
console.log("Data successfully saved: ", data);
window.location.href = "/Cards/Learning";
} else {
console.error("Error saving card: ", data.message);
}
}))
}
document.addEventListener('DOMContentLoaded', function() {
let newCard = document.querySelector('.new-card');
newCard.addEventListener('click', function() {
addCard();
});
document.querySelector('form.cards').addEventListener('submit', function() {
saveCardDataToServer();
});
});
View
@model CardList
<!DOCTYPE html>
<html lang="en">
<head>
<script src="~/js/script.js">
</script>
<link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet"
integrity="sha384-QWTKZyjpPEjISv5WaRU9OFeRpok6YctnYmDr5pNlyT2bRjXh0JMhjY6hW+ALEwIH" crossorigin="anonymous" asp-append-version="true">
</head>
<body>
<main class="main">
<div class="container">
<div class="new-module d-flex justify-content-between mt-5">
<h1>Create new module</h1>
<a class="btn btn-primary" asp-controller="Cards" asp-action="learning" type="submit">Создать</a>
</div>
<div class="card mt-5 p-2 pb-3">
<h3>Title</h3>
<input class="form-control w-100" placeholder="Enter a name">
</div>
<form asp-controller="Cards" asp-action="Create" method="post" class="cards">
<div class="card mt-6" id="card">
<div class="header d-flex justify-content-between p-3">
<h4 class="card-counter">1</h4>
</div>
<div class="card-body row">
<div class="term col">
<h3>Term</h3>
<input class="form-control w-100" name = "term" >
</div>
<div class="definition col">
<h3>Definition </h3>
<input class="form-control w-100" name = "definition" >
</div>
</div>
</div>
<input type="submit" value="Create" id="create-cards" class="btn btn-primary mt-2"/>
</form>
<button class="new-card w-100 d-flex justify-content-center align-items-center mt-4 mt-s rounded-2" style="height: 5rem" type="button">
<h3>+ Add card</h3>
</button>
</div>
</main>
</body>
</html>
Models
public class Card
{
public int CardId { get; set; }
[Required]
public string Term { get; set; } = string.Empty;
public string Definition { get; set; } = string.Empty;
}
public class CardList : IEnumerable<Card>
{
public List<Card> Cards { get; set; }
public CardList()
{
Cards = new List<Card>();
}
public IEnumerator<Card> GetEnumerator()
{
return Cards.GetEnumerator();
}
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
}
Controller
public class CardsController : Controller
{
public IActionResult Learning()
{
var cards = CardsRepository.GetCards();
return View(cards);
}
public IActionResult Create()
{
return View();
}
[HttpPost]
[Route("Cards/Create/")]
public IActionResult Create([FromBody] CardList cards)
{
if (cards != null)
{
foreach (var card in cards)
{
if (!string.IsNullOrWhiteSpace(card.Term) && !string.IsNullOrWhiteSpace(card.Definition))
{
CardsRepository.AddCard(card);
}
}
return Json(new { success = true, message = "Card saved successfully " });
}
var errors = ModelState.Values.SelectMany(v => v.Errors).Select(e => e.ErrorMessage);
return Json(new { success = false, message = "Validation error", errors = errors });
}
}
If IEnumerable is not implemented in the CardList controller, Create([FromBody] CardList cards) will get the correct data.
I suggest not extending IEnumerable at all. Go simpler.
public class Card
{
public int CardId { get; set; }
[Required]
public string Term { get; set; } = string.Empty;
public string Definition { get; set; } = string.Empty;
}
public class Deck
{
public List<Card> Cards { get; set; }
public Deck()
{
Cards = new List<Card>();
}
}
Which gives you simple json to work from:
{
"Cards": [
{
"CardId": 1,
"Term": "Term 1",
"Definition": "Definition 1"
},
{
"CardId": 2,
"Term": "Term 2",
"Definition": "Definition 2"
},
{
"CardId": 3,
"Term": "Term 3",
"Definition": "Definition 3"
}
]
}
It's best practice to make your DTO's (data transfer objects) as simple as possible.