title: How to set a windows form as the main form of the application? C#
body: <p>I'm using Visual Studio C# and I got stuck in making a new form become the main one. I need the application to be closed when it get closed and I want to close the previous form without closing the application.</p>
  
  <p>Current attempt (won't work):</p>
  
  <pre><code>FormClass newForm = new FormClass();
  newForm.Show()
  
  previousForm.Close()
  </code></pre>