Opening a DocFile

Opening an existing DocFile is very similar to creating one. You might think that the API call to open a DocFile would be StgOpenDocFile, but you'd be wrong... The API call is StgOpenStorage, remember that a DocFile is itself a storage i.e. the root storage, just as the root directory is itself a directory.


   procedure TestOpen;
   var
      Hr : HResult;
      RootStorage : IStorage;
   begin

         {Try open the DocFile}
      Hr := StgOpenStorage(  'c:\Temp\MyDocFile.ole',
                          nil,
                          STGM_READWRITE or
                          STGM_DIRECT or STGM_SHARE_EXCLUSIVE,
                          nil,
                          0,
                          RootStorage
                        );

         {Was is opened?}
      if(   SUCCEEDED(  Hr  )   ) then
      begin

         (* Success *)

      end
      else begin

         (*  Fail  *)

      end;
   end;

Before opening a file you might want to check if it is in fact a DocFile. This is accomplished by using the StgIsStorageFile function. Pass the name of the file as the only parameter (UniCode string) and the function will return S_OK if it is a DocFile.


   
   if(   StgIsStorageFile(  'c:\Temp\MyDocFile.ole'  ) <> S_OK   ) then
      ShowMessage(  'Not a doc file'  )
   else
      ShowMessage(  'Valid DocFile'  );