To save a URL as an MHT file (Microsoft "Multipurpose Internet Mail Extension HTML"a Web Archive File), reference the Microsoft ActiveX Data Objects 2.7 and Microsoft CDO libraries and use the following code:
void SaveWebPageToMHTFile( string url, string filePath)
{
CDO.Message msg = new CDO.MessageClass();
ADODB.Stream stm = null ;
msg.MimeFormatted =true;
msg.CreateMHTMLBody(url,
CDO.CdoMHTMLFlags.cdoSuppressNone,
"" ,"" );
stm = msg.GetStream();
stm.SaveToFile(filePath,
ADODB.SaveOptionsEnum.adSaveCreateOverWrite);
msg=null;
stm.Close();
}