参考链接：
https://www.baidu.com/s?tn=88093251_84_hao_pg&wd=datagridview表头合并&ie=utf-8
https://blog.csdn.net/qq_35106907/article/details/85672043
https://www.baidu.com/s?tn=44004473_48_oem_dg&ie=utf-8&wd=datagridview二维表头
https://www.baidu.com/s?tn=44004473_48_oem_dg&ie=utf-8&wd=DataGridView列标题合并
https://www.cnblogs.com/yellowapplemylove/archive/2011/04/19/2021581.html
以下，记录于2022年1月19日13点39分
先把资料列出来，第一个是我正在做的
- https://www.cnblogs.com/dachuang/p/8780006.html
- https://blog.csdn.net/weixin_34124651/article/details/94050996
- https://bbs.csdn.net/topics/200025579
- https://www.baidu.com/s?tn=88093251_84_hao_pg&wd=DataGridView合并行标题&ie=utf-8
- https://www.baidu.com/s?tn=44004473_48_oem_dg&ie=utf-8&wd=DataGridView列标题合并
- https://www.cnblogs.com/yellowapplemylove/archive/2011/04/19/2021581.html
- https://www.baidu.com/s?tn=44004473_48_oem_dg&ie=utf-8&wd=datagridview二维表头
- https://blog.csdn.net/qq_35106907/article/details/85672043
- https://www.baidu.com/s?tn=88093251_84_hao_pg&wd=datagridview表头合并&ie=utf-8
- https://www.baidu.com/s?ie=utf-8&f=8&rsv_bp=1&tn=88093251_84_hao_pg&wd=DataGridView合并列标题&oq=DataGridView%25E4%25BA%258C%25E7%25BB%25B4%25E5%2588%2597%25E6%25A0%2587%25E9%25A2%2598&rsv_pq=9b467b27000bf9ac&rsv_t=c3b9z7TknEyRpRK0g0BZ0lqJOEOdFLvUZQxnBoBqEZG2CZw9KtR9MCDBJ871FmZRczkmR9ka8gJp&rqlang=cn&rsv_dl=tb&rsv_enter=1&rsv_sug3=10&rsv_sug1=6&rsv_sug7=100&rsv_sug2=0&rsv_btype=t&inputT=1325&rsv_sug4=1848
- https://blog.csdn.net/stuqbx/article/details/8524515
- https://docs.microsoft.com/zh-cn/dotnet/api/system.windows.forms.datagridview.columnheadersheightsizemode?view=windowsdesktop-6.0
- https://docs.microsoft.com/zh-cn/dotnet/api/system.windows.forms.datagridviewcolumnheadersheightsizemode?view=windowsdesktop-6.0