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Seb Nilsson
Seb Nilsson

Posted on • Originally published at on

HTML Encode TagHelper in ASP.NET Core

For a specific scenario recently, I wanted to display the HTML-encoded output of a TagHelper in ASP.NET Core. So I wanted to use the TagHelper, but not output its actual result, but see the raw HTML which would have been included in my template.


So I created another TagHelper, which allows me to wrap any HTML, inline code in ASP.NET Core and other TagHelpers, and get all the content inside the TagHelper's tag to be HTML-encoded, like this:

    <a href="@Url.Action("Index")">Read More</a>
    <my-other-tag-helper />

From this, I will get the raw HTML of the link with an UrlHelper-result, the result of the HTML-helper and the result of my other TagHelper.

The source-code for the html-encode-TagHelper is as follows:

[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;

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