title: Create app config file if doesn't exist C#
body: <p>When I try to open my app config file by</p>
  
  <pre><code>ConfigurationManager.OpenExeConfiguration(filePath);
  </code></pre>
  
  <p>it returns an exception, because there is no file. But I need to create this file in this case. But as I know, config file create by adding at VS like <a href="http://msdn.microsoft.com/en-us/library/ms184658.aspx">How to: Add an Application Configuration File to a C# Project</a> </p>
  
  <p>So, how to create this file in other way?</p>