 <p>Keys inside <code>appSettings</code> are retrieved as <code>NameValueCollection</code> which by definition</p> <blockquote> <p>Represents a collection of associated String keys and String values that can be accessed either with the key or with the index.</p> </blockquote> <p>So you can have only the data type <code>string</code> as <code>value</code> for an AppSettings <code>key</code></p> <p>And yes, <code>AppSettings</code> is the only place where you can store your settings.<br> MSDN defines AppSettings like this.</p> <blockquote> <p>Contains custom application settings, such as file paths, XML Web service URLs, or any information that is stored in the.ini file for an application.</p> </blockquote>