title: Visual Studio 2017 the connection string could not be found in application settings
body: <p>For connection database and reading data, I am using a dataset which read connection string from Web.config file. Everything working in Visual Studio 2013. But when I opened this project in Visual Studio 2017, I can't configure. It errors:</p>
  
  <blockquote>
    <p>Unable to find connection string xxxx. the connection string could not be found in application settings or the data provider associated with the connection string could not be loaded</p>
  </blockquote>
  
  <p><a href="https://i.stack.imgur.com/EmAhR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/EmAhR.png" alt="enter image description here"></a></p>