title: In C# and VS2012, How do I find all lines that make use of a particular "using" directive?
body: <p>I wish I could find a better way to word the title, but hopefully it becomes more clear as I explain. I'm also hoping that Visual Studio supports what I'd like to use it for, or that someone is aware of a plug-in or slick workaround that will answer my question.</p>
  
  <p><strong>Really simple example:</strong></p>
  
  <pre><code>using System.IO
  public class MyClass
  {
      if (File.Exists("myfile.txt"))
      {
          //Do something that doesn't involve System.IO
      }
  }
  </code></pre>
  
  <p>I want to point at a particular using (like System.IO) and find every line that relies on the using directive, such as the "File.Exists" line.</p>
  
  <p>In VS2012 you can right-click the "using" directives at the beginning of a file and select Organize Usings > Remove Unused Usings. This is great, but I want to sort of do the reverse of that.</p>
  
  <p><strong>A solution that is clumsy and time consuming.</strong>
  One method would be to erase a using line, and attempt to build, and then look through all the errors to try and find the appropriate ones. This answer feels like a hack, takes time, and produces the result as a list of errors.</p>
  
  <p><strong>The Circumstance.</strong>
  I'm refactoring a bunch of code. One of the classes has over 4000 lines of code and 13 using directives. In looking at the in house references, I can tell that this 800lbs gorilla class is referencing namespaces from very different parts of the system. I want to identify the areas of the code that make use of a particular using in order to help me segment this class up. Simply compiling with a missing using takes time and doesn't produce the results in a helpful format.</p>
  
  <p>To try and phrase the question another way:
  "How do I get visual studio to show me all the lines of code that rely on a particular using directive?"</p>