Cant pass renderFragment to component

[Amir0715]

Hi, I'm learning from your website. I have reached the lesson https://blazor-university.com/templating-components-with-renderfragements/passing-placeholders-to-renderfragments/
And I ran into the problem that I can't pass the template to the DataListTemplate parameter of the RenderFragment<RendetFragment> type of the DataList component. I get the following error during the build:

D:\projects\MS.CRM.Clients\MS.CRM.BlazorWebAssembly\Microsoft.NET.Sdk.Razor.SourceGenerators\Microsoft.NET.Sdk.Razor.SourceGenerators.RazorSourceGenerator\Pages_Debug_razor.g.cs(532,283,532,293): error CS0234: The type or namespace name 'AspNetCore' does not exist in the namespace '__Blazor.Microsoft' (are you missing an assembly reference?)

DataList.razor:

@typeparam T

@if (DataListTemplate == null)
{
  <ul>
    @foreach (var item in Data ?? Array.Empty<T>())
    {
      @ItemTemplate(item)
    }
  </ul>
}
else
{
  @DataListTemplate(
    @:@{
      foreach (var item in Data ?? Array.Empty<T>())
      {
        ItemTemplate(item)
      }
    }
    )
}

@code {

    [Parameter]
    public IEnumerable<T> Data { get; set; } = null!;

    [Parameter]
    public RenderFragment<T> ItemTemplate { get; set; } = null!;

    [Parameter]
    public RenderFragment<RenderFragment>? DataListTemplate { get; set; } = item => @item;

    protected override void OnInitialized()
    {
        if (Data == null) throw new ArgumentNullException(nameof(Data));
        if (ItemTemplate == null) throw new ArgumentNullException(nameof(ItemTemplate));
        base.OnInitialized();
    }
}

How i use:

@page "/debug"

<div class="container">
    <DataList Data="@Persons">
        <DataListTemplate Context="Data">
            <table>
                <thead>
                <tr>
                    <th>Salutation</th>
                    <th>Given name</th>
                    <th>Family name</th>
                </tr>
                </thead>
                <tbody>
                    @Data
                </tbody>
            </table>
        </DataListTemplate>
        <ItemTemplate>
            <li @key="context">@context.Name (Age: @context.Age)</li>
            @* <li>@context</li> *@
        </ItemTemplate>
    </DataList>
</div>

@code {

    public class Person
    {
        public Person(string Name, int Age)
        {
            this.Name = Name;
            this.Age = Age;
        }

        public string Name { get; init; }
        public int Age { get; init; }
    }

    IEnumerable<Person> Persons;

    protected override void OnInitialized()
    {
        base.OnInitialized();
        Persons = new[]
        {
            new Person("Alex", 10),
            new Person("Lecy", 20),
            new Person("Suzi", 15),
        };
    }

}

Pls, can you help me?
I also get error hint in my ide for Wig-Pig syntax: