public Heading GetHeading(int index) // 获取摘要(TOP指令) { if (Connected) { String RawEmail = SendCmd("TOP " + index + " 0", true); if (RawEmail.Contains("deleted") || RawEmail.Contains("not exists") || RawEmail == "") // 若邮件已经被删除,则不处理 { return(null); } return(MIME.GetHeading(RawEmail, index)); } return(null); }