title: Using .NET library in Windows Phone 8.1 application
body: <p>I want to create Windows Phone 8.1 application in C#. I have a commercial .NET library I need to use which, according to the documentation, is compatible with Windows and Windows Mobile operating systems. When I add a reference to this library in my project and compile, I receive the following error: <code>Cannot find type System.Collections.CollectionBase in module mscorlib.dll</code>.</p>
  
  <p>Is there any way to use this library in Windows Phone 8.1 application?</p>