The Download Excel File button retreives a list of U.S. States in JSON format from the MySafeInfo Data API.
The JSON data is converted to a strongly typed List<State> using Json.NET (Newtonsoft.Json).
The List<State> is converted to a DataTable using ToDataTable extension method.
The DataTable is converted to a byte[] using ToExcel extension method that uses EPPlus.
The byte[] is then simply written back to the browser using Response.BinaryWrite.

The Read Excel File button reads the states.xlsx Excel file in to a StreamReader.
The StreamReader underlying stream is converted to a DataTable using ToDataTable extension method.
The DataTable is converted to a List<State> using ToList extension method.
The List<State> is then serialized and output to a Literal to confirm that the Excel file was in fact read successfully.