c# - add value to subject field in reply window - MS OUTLOOK -

i beginner in c# .net programming. application i'm developing generate unique number , want pass value subject field in reply window of ms outlook.

i have tried using microsoft.office.interop.outlook create new mail cant around reply inbox, should addin used?

here have example of creating email using outlook interop. can set int subject field see below.

 using outlook = microsoft.office.interop.outlook;    //create email settings  outlook.application outlookapp = new outlook.application();  outlook.mailitem mailitem = (outlook.mailitem)outlookapp.createitem(outlook.olitemtype.olmailitem);  mailitem.subject = mailsubject;  mailitem.attachments.add(totalpath);  mailitem.body = mailbody;  mailitem.importance = outlook.olimportance.olimportancenormal;  try  {      //try open outlook, set message if not possible open outlook      mailitem.display(true);  }  catch (exception ex)  {      messagebox.show(ex.message);      return false;  }