title: Link error when calling RUNTIME_CLASS on new class
body: <p>I have a Visual Studio 2010 project done on MFC. I receive these errors:</p>
  
  <pre><code>2&gt;COrderContentsItemsDocument.obj : error LNK2028: unresolved token (0A0001CA) "public: static struct CRuntimeClass * __stdcall COrderContentsItem::GetThisClass(void)" (?GetThisClass@COrderContentsItem@@$$FSGPAUCRuntimeClass@@XZ) referenced in function "public: virtual struct CRuntimeClass * __thiscall COrderContentsItemsDocument::GetItemsRuntimeClass(void)" (?GetItemsRuntimeClass@COrderContentsItemsDocument@@$$FUAEPAUCRuntimeClass@@XZ)
  
  2&gt;COrderContentsItemsDocument.obj : error LNK2019: unresolved external symbol "public: static struct CRuntimeClass * __stdcall COrderContentsItem::GetThisClass(void)" (?GetThisClass@COrderContentsItem@@$$FSGPAUCRuntimeClass@@XZ) referenced in function "public: virtual struct CRuntimeClass * __thiscall COrderContentsItemsDocument::GetItemsRuntimeClass(void)" (?GetItemsRuntimeClass@COrderContentsItemsDocument@@$$FUAEPAUCRuntimeClass@@XZ)
  
  2&gt;..\..\Output\Win32\Debug_Unicode\MindSalesManager.exe : fatal error LNK1120: 2 unresolved externals
  </code></pre>
  
  <p>After some research, I disocovered,that the problem comes when I call</p>
  
  <pre><code>RUNTIME_CLASS(COrderContentsItem)
  </code></pre>
  
  <p>So, this class is a new one that I copied from another already existing. So I am wondering to discover what is the problem.</p>
  
  <p>Cheers, 
  Sérgio</p>