Blazor troubles with cascading InputSelect

index.razor

@page "/"

<EditForm Model="@Model">

    First
    <InputSelect @bind-Value="Model.First" class="form-control" @oninput="FirstChanged">
        @foreach (var item in FirstList)
        {
            <option value="@item">@item</option>
        }
    </InputSelect>

    Second
    <InputSelect @bind-Value="Model.Second" class="form-control">
        @foreach (var item in SecondList)
        {
            <option value="@item">@item</option>
        }
    </InputSelect>

</EditForm>

@code
{
    public class Record
    {
        public string First { get; set; }
        public string Second { get; set; }
    }

    public Record Model { get; set; } = new Record();

    public List<string> FirstList { get; set; } = new List<string> { "A", "B", "C", "D" };

    public List<string> SecondList { get; set; } = new List<string>();

    public void FirstChanged()
    {
        SecondList = Enumerable.Range(1, 5).Select(x => $"{Model.First}-{x}").ToList();
        StateHasChanged();
    }
}