title: Custom Tag Helper - replace the html tag
body: <p>I've created a Tag Helper that reads a txt file that contains meta tags and writes the content to the page.
  But the original tag doesn't change after Process is executed.
  I want to completely replace the original tag with the content of the txt file.</p>
  
  <p><strong>Tag Helper</strong></p>
  
  <pre><code>[HtmlTargetElement("LC_meta")]
  public class MetaTagHelper : TagHelper
  {
      private IHostingEnvironment _env;
  
      [HtmlAttributeName("filename")]
      public string Filename { get; set; } = "default.txt";
  
      public MetaTagHelper(IHostingEnvironment env)
      {
          _env = env;
      }
  
      public override void Process(TagHelperContext context, TagHelperOutput output)
      {
         output.Content.SetContent(System.IO.File.ReadAllText(System.IO.Path.Combine(_env.WebRootPath, "META", this.Filename)));
      }
  }
  </code></pre>
  
  <p><strong>and this is the original tag's:</strong></p>
  
  <pre><code>&lt;LC_meta /&gt;
  &lt;LC_meta filename="sample.txt" /&gt;
  </code></pre>
  
  <p>I'm kinda stuck, so many thanks in advance!</p>