我找不到这个问题的更一般的标题，但是基本上我有一个Excel列标题字符串的列表，例如：
var lst = new List<string> {"A4","B4","C4","D4","E4","F4","G4","BQ4","J4","K4","L4","M4","N4","O4","P4","Q4","R4","S4","BX4","BY4","BZ4","CA4","BW4","AH4","AC4","AD4","AE4","AG4","AI4","AJ4","BO4","BP4","BR4","BS4","BU4","BT4","BV4","AK4","AL4","AM4","AN4","AT4","AU4","AS4","AR4","AO4","AP4","AQ4","BA4","BB4","BC4","BE4","BF4","BG4","BH4","BI4","BJ4","BK4","BL4","BM4","BN4","CB4","CC4","W4","I4","U4","V4","CD4"};
我需要按字母组对它进行排序，就像A-Z一样，然后在标题中添加2个字母，AA，AB，.. BQ，依此类推。就像它们按Excel工作表的顺序显示一样。