In .NET, you use Debug.WriteLine() to write ODS messages. This requires that your assemblies be built with DEBUG information to see the ODS messages. When working with ASP.NET pages, you have a some options to achieve this (the easiest couple are listed here):
<%@ Page language="c#" Debug="true"%> Testing:<br> <% System.Diagnostics.Debug.Write("Testing"); %>
<system.web> <compilation debug="true" defaultLanguage="c#" /> </system.web>
Disclaimer The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.