@typeparam TItem

@if (items == null)
{
    @Loading
}
else if (!items.Any())
{
    @Empty
}
else
{
    <div class="list-group @ListGroupClass">
        @foreach (var item in items)
        {
            <div class="list-group-item">
                @Item(item)
            </div>
        }
    </div>
}

@code {
    IEnumerable<TItem> items;

    [Parameter] public Func<Task<IEnumerable<TItem>>> Loader { get; set; }
    [Parameter] public RenderFragment Loading { get; set; }
    [Parameter] public RenderFragment Empty { get; set; }
    [Parameter] public RenderFragment<TItem> Item { get; set; }
    [Parameter] public string ListGroupClass { get; set; }

    protected override async Task OnParametersSetAsync()
    {
        items = await Loader();
    }
}