Export Data from gridview to Excel

//Create or Open File using File Stream with ReadWrite Mode and Access.
FileStream fs = new FileStream(Excelpath, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);

fs.Close();
fs.Dispose();

//Use String Writer to Write Html in File
using (StringWriter sw = new StringWriter())
{

   //Use HTML Writer to fill Html Rendering Script in StringWriter  in File
   using (HtmlTextWriter htw = new HtmlTextWriter(sw))
   {

     //Render Gridview in HTML Writer 
     GridView1.RenderControl(htw);

     //Write all text in File using String Writer
     File.WriteAllText(Excelpath, sw.ToString());
     htw.Close();
   }
   sw.Close();
}