title: When to use IDataReader and when to use DataReader?
body: <p>I know that <code>IDataReader</code> is the interface and <code>DataReader</code> is the concrete type but I still don't know when to use each one. I need to iterate through the data which is possible using both <code>Datareader</code> and <code>IDataReader</code>. Is there a better way to decide when to use the interface or the concrete type?</p>