InternalUtils.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Plotly.NET.CSharp
{
 [AttributeUsage(AttributeTargets.Class)]
 internal class TypeFormatterSourceAttribute : Attribute
 {
 public TypeFormatterSourceAttribute(Type formatterSourceType)
 {
 FormatterSourceType = formatterSourceType;
 }

 public Type FormatterSourceType { get; }

 public string[] PreferredMimeTypes { get; set; }
 }
 internal class MyConventionBasedFormatter
 {
 public string MimeType { get; set; }

 public bool Format(object instance, TextWriter writer)
 {
 if (instance is Plotly.NET.GenericChart myObj)
 {
 writer.Write($"<div>Custom formattering for {myObj}</div>");
 return true;
 }
 else
 {
 return false;
 }
 }
 }
 internal class MyConventionBasedFormatterSource
 {
 public IEnumerable<object> CreateTypeFormatters()
 {
 yield return new MyConventionBasedFormatter { MimeType = "text/html" };
 }
 }

}