游戏中的一些聊天框的：上、下方向键的回溯记录方法

最要代码：

        private static readonly List sendRecordList = new List();

        private static int sendRecordListIdx = 0;

        private static void addSendRec(string msg)
        {
            if (string.IsNullOrEmpty(msg)) return;

            if(sendRecordList.Count>10)sendRecordList.RemoveAt(0);
            sendRecordList.Add(msg);

            sendRecordListIdx = sendRecordList.Count;
        }

        private static string upGetSendRec()
        {
            if (sendRecordList.Count == 0) return string.Empty;
            sendRecordListIdx--;
            if (sendRecordListIdx < 0) sendRecordListIdx = 0;
            return sendRecordList[sendRecordListIdx];
        }

        private static string downGetSendRec()
        {
            if (sendRecordList.Count == 0) return string.Empty;
            sendRecordListIdx++;
            if (sendRecordListIdx > (sendRecordList.Count - 1)) sendRecordListIdx = sendRecordList.Count - 1;
            return sendRecordList[sendRecordListIdx];
        }

调用的地方：

            if (e.KeyCode == Keys.Up)
            {
                this.textBox_send_chat_txt.Text = upGetSendRec();
            }
            else if (e.KeyCode == Keys.Down)
            {
                this.textBox_send_chat_txt.Text = downGetSendRec();
            }