C / C++ / MFC

1. Call the CWnd::DragAcceptFiles method for your top-level window (e.g. I called it for a dialog window in the dialog's OnInitDialog)
2. Override and implement the window's CWnd::OnDropFiles method - here's some code I've knocked together that demonstrates how it works:
   

   void CMyDlg::OnDropFiles(HDROP hDropInfo)
   {
      const UINT nFiles = DragQueryFile(hDropInfo, (UINT)-1, 0, 0);
      std::vector<CString> files;
      for(UINT i=0;i<nFiles;++i)
      {
         CString thisFile;
         const UINT nChars = DragQueryFile(hDropInfo, i, thisFile.GetBufferSetLength(MAX_PATH), MAX_PATH);
         files.push_back(thisFile);
      }
   
      CDialog::OnDropFiles(hDropInfo);
   }

zon_cpp wrote:

i know that name of the parent of exe files in windows, is explorer.exe.

1. It declares and defines the function GetSample
2. The function declares and defines a local static variable called state. As it's static, this variable retains it's value after the function exits even though it's local to the function
3. The function returns a reference to state. It looks like it's trying to implement some sort of a singleton for the class Sample