Fill excel doc from C#

public static void XLSWriter(string filename, string desiredcell, double number)
{
  try
  {
    string path = @"c:\Documents and Settings\rdockter\My Documents\" + file + "";
    string connectionstring = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + path + ";Extended Properties=\"Excel 8.0;HDR=NO;READONLY=FALSE\"";
    OleDbConnection conn = new OleDbConnection(connectionstring);
    OleDbCommand command = new OleDbCommand();
    conn.Open();
    command.Connection = conn;
    string Sql = "UPDATE [Sheet1$" + desiredcell + ":" + desiredcell + "] SET F1='" + number + "';";
    command.CommandText = Sql;
    command.ExecuteNonQuery();
    conn.Close();
  }
  catch (OleDbException ex)
  {
    Console.WriteLine("Error: {0}", ex);
  }
}