The file opened using the API, can you help check why the file is in 'not opened' status?

The code is as follows:

public class SWPackGo
{
   public static void OpenFile()
   {
       SldWorks swApp = new SldWorks();
       swApp.Visible = true;

       int errors = 0, warnings = 0;

       swApp.OpenDoc6(
           @"C:\\Users\\zw\\Desktop\\3WG2252-54-155KA外协外协.SLDDRW",
           (int)swDocumentTypes_e.swDocDRAWING,
           (int)swOpenDocOptions_e.swOpenDocOptions_Silent,
           "",
           ref errors,
           ref warnings);
   }
}