If I create an app.config file in a console apps like this

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings>
    <add key ="key1" value ="val1"/>     
  </appSettings>
</configuration>

and access the same from the console application like

object sourcePath = System.Configuration.ConfigurationManager.AppSettings["key1"];

or by

object sourcePath = System.Configuration.ConfigurationSettings.AppSettings["key1"];

I am able to get the value.

But if I do the same thing in a class library project, I am getting a null value. Why? Where I am making mistake? I have added the proper reference System.Configuration. I am using C# 3.0