title: Is reading app.config expensive?
body: <p>No question I am yet to be hit by any read speed bottleneck. I am asking to know; if reading app.config frequently is a bad programming choice. I have known of database operations getting expensive.</p>
  
  <p><strong>In my case I am not reading my own application's app.config, but of another project's</strong>, like this: </p>
  
  <pre><code>private string GetAppConfigValue(string key)
  {
      ExeConfigurationFileMap fileMap = new ExeConfigurationFileMap();
      fileMap.ExeConfigFilename = GetConfigFilePath();
      Configuration appConfig = ConfigurationManager.OpenMappedExeConfiguration(fileMap, ConfigurationUserLevel.None);
      return appConfig.AppSettings.Settings[key].Value;
  }
  </code></pre>
  
  <p>Scenario: I have a manager class (and only one such class) where I have to read few values (3 to 4) from a config file specified by a physical path, <strong>but many times</strong>. Need I have few member variables to store the values from app.config file? What would be the best approach. Thanks.</p>