c# - Word Document SaveAs2 in Format wdFormatDocument97 -

i'm using microsoft interop word version 15.0.0.0 in order create new word document, insert text it, , save it.

when i'm saving using following command:

document.saveas2(wordfilepath); 

the document saved in format docx.

but when i'm saving using following command:

document.saveas2(wordfilepath, microsoft.office.interop.word.wdsaveformat.wdformatdocument97); 

the document seemingly saved word-97 doc (windows explorer display word-97 doc icon , type), internally saved docx (i can see in 2 ways: has same size of corresponding docx, , when open word-2016 , select saveas, default save format docx!).

how can save document in real document-97 format?

here's function used create new word document, type depends on extension (doc vs. docx) of given file path:

public static void texttomsworddocument(string body, string wordfilepath) {     microsoft.office.interop.word.application winword = new microsoft.office.interop.word.application();     winword.visible = false;     object missing = system.reflection.missing.value;     microsoft.office.interop.word.document document = winword.documents.add(ref missing, ref missing, ref missing, ref missing);     if (body != null)     {         document.content.setrange(0, 0);         document.content.text = (body + system.environment.newline);     }     if (system.io.path.getextension(wordfilepath).tolower() == "doc")         document.saveas2(wordfilepath, microsoft.office.interop.word.wdsaveformat.wdformatdocument97);     else // assuming "docx" extension:         document.saveas2(wordfilepath);     document.close(ref missing, ref missing, ref missing);     document = null;     winword.quit(ref missing, ref missing, ref missing);     winword = null; } 

and here's code used call function:

texttomsworddocument("abcdefghijklmnopqrstuvwxyz", "text.doc"); texttomsworddocument("abcdefghijklmnopqrstuvwxyz", "text.docx"); 

it's been rather stupid error...compare ‘ == ".doc" ’ instead of ‘ == "doc"...

i didn't notice due fact when saveas2 received file path extension ".doc" , no wdsaveformat, - strangely enough- created word document file had problem explained here...