as my senario is like i had a Corrupted .docx file , i can't open it and read it,so what i have to do is read the content from it and make a duplicate of that file.
i got the solution as i didn't copy but Recovered the Corrupted .docx file and saveas it with another name.
Microsoft.Office.Interop.Word.Application wordApp = new Microsoft.Office.Interop.Word.Application();
object file = path;
object nullobj = System.Reflection.Missing.Value;
Microsoft.Office.Interop.Word.Document doc = wordApp.Documents.Open(
ref file, ref nullobj, ref nullobj,
ref nullobj, ref nullobj, ref nullobj,
ref nullobj, ref nullobj, ref nullobj,
ref nullobj, ref nullobj, ref nullobj, true);
Object oSaveAsFile = (Object)"C:\\SampleDoc.docx";
doc.SaveAs2(oSaveAsFile, Microsoft.Office.Interop.Word.WdSaveFormat.wdFormatXMLDocument);
doc.Close(ref nullobj, ref nullobj, ref nullobj);
wordApp.Quit(ref nullobj, ref nullobj, ref nullobj);