Render everything inside tag as encoded HTML

HtmlEncodeTagHelper.cs

[HtmlTargetElement("html-encode", TagStructure = TagStructure.NormalOrSelfClosing)]
public class HtmlEncodeTagHelper : TagHelper
{
    public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
    {
        var childContent = output.Content.IsModified
                                ? output.Content.GetContent()
                                : (await output.GetChildContentAsync()).GetContent();

        string encodedChildContent = WebUtility.HtmlEncode(childContent ?? string.Empty);

        output.TagName = null;
        output.Content.SetHtmlContent(encodedChildContent);
    }
}