Excel to HTML

ExcelToHtml.cs

using Sylvan.Data.Excel;

using var r = ExcelDataReader.Create("Data.xlsx");
r.WriteHtmlTable(Console.Out);

static class DataExtensions
{
    public static long WriteHtmlTable(this System.Data.Common.DbDataReader data, TextWriter writer)
    {
        long count = 0;

        writer.WriteLine("<table>");

        writer.WriteLine("<tr>");
        for (int i = 0; i < data.FieldCount; i++)
        {
            writer.Write("<th>");
            var name = data.GetName(i);
            writer.Write(System.Net.WebUtility.HtmlEncode(name));
            writer.WriteLine("</th>");
        }
        writer.WriteLine("</tr>");

        while (data.Read())
        {
            count++;
            writer.WriteLine("<tr>");
            for (int i = 0; i < data.FieldCount; i++)
            {
                writer.Write("<td>");
                var value = data.GetValue(i);
                var str = value?.ToString() ?? string.Empty;
                writer.Write(System.Net.WebUtility.HtmlEncode(str));
                writer.WriteLine("</td>");
            }
            writer.WriteLine("</tr>");
        }

        writer.WriteLine("</table>");
        return count;
    }
}