Return a view as download html file

HtmlFileResult.cs

	public class HtmlFileResult : FileResult
	{
		private readonly ControllerContext controllerContext;
		private readonly string viewToRender;
		private readonly object model;

		public HtmlFileResult(ControllerContext controllerContext, string viewToRender, object model, string fileDownloadName) : base("text/html")
		{
			if (string.IsNullOrWhiteSpace(viewToRender))
			{
				throw new ArgumentException("The view name is required", nameof(viewToRender));
			}
			if (string.IsNullOrWhiteSpace(fileDownloadName))
			{
				throw new ArgumentException("The file name is required", nameof(fileDownloadName));
			}

			FileDownloadName = fileDownloadName;
			this.controllerContext = controllerContext ?? throw new ArgumentNullException(nameof(controllerContext));
			this.viewToRender = viewToRender;
			this.model = model ?? throw new ArgumentNullException(nameof(model));
		}

		protected override void WriteFile(HttpResponseBase response)
		{
			const int DefaultStreamWriterBufferSize = 4096;
			var result = ViewEngines.Engines.FindView(controllerContext, viewToRender, null);
			using (TextWriter textWriter = new StreamWriter(response.OutputStream, Encoding.UTF8,
				bufferSize: DefaultStreamWriterBufferSize, leaveOpen: true))
			{
				var viewContext = new ViewContext(controllerContext, result.View, new ViewDataDictionary(model), controllerContext.Controller.TempData, textWriter);
				result.View.Render(viewContext, textWriter);
				result.ViewEngine.ReleaseView(controllerContext, result.View);
			}
		}
	}