title: DirectoryInfo throws "Argument Exception: The path is not of a legal form" for the correct path
body: <p>When I use DirectoryInfo with a specific path (say @"C:\") in my ASP.NET MVC application, it returns ok but when I try to use the exactly same path in my external C# library, it throws the above exception. I have checked the path a thousand time and the path is legal. Can somebody tell me the reason?</p>
  
  <p>Edit:
  Here's the code: </p>
  
  <pre><code>var di = new DirectoryInfo("C:\\App\\Files\\");
      //        var file = di.GetFiles(Id + ".*").First();
      //        if (file != null) return file.FullName;
      //        return string.Empty;
  </code></pre>
  
  <p>The above code is used inside a property.</p>
  
  <p>Thanks.</p>