When deserializing a json string, it doesn't include the data

September 24, 2023

When trying to deserialize a json string to an object of type Cart, the result is always empty even though the string contains data.

Code:

string str = this.HttpContext.Session.GetString("cart"); // {"Lines":[{"Id":9,"Count":1}]}
Cart c = JsonSerializer.Deserialize<Cart>(str);

c.Lines.Count() is 0;

Cart.cs:

[Serializable]
public sealed class Cart
{
    private readonly ICollection<CartLine> _lines = new Collection<CartLine>();

    public void Add(CartLine line)
    {
        _lines.Add(line);
    }

    public void Remove(int productId)
    {
        CartLine tmp = _lines.Single(cr => cr.Id == productId);
        _lines.Remove(tmp);
    }

    public IEnumerable<CartLine> Lines => _lines;
}

CartLine.cs:

[Serializable]
public sealed class CartLine
{
    public int Id { get; set; }
    public int Count { get; set; }
}

>Solution :

property Lines doesn’t have a setter, should be

    public IEnumerable<CartLine> Lines
    {
        get { return _lines; }
        init { _lines = new Collection<CartLine>(value.ToList()); }

    }