repeatertaghelper.cs

public class RepeaterTagHelper : TagHelper
{
    public int Count { get; set; }

    public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
    {
        output.TagName = null;
        for (int i = 0; i < Count; i++)
        {
            output.Content.Append(await context.GetChildContentAsync(useCachedResult: false));
        }
    }
}