An item with the same key has already been added.

开发环境：.Net Core 3.1，NPOI 2.6.0

前言：复制行数据时，提示错误如下：

An item with the same key has already been added. Key: 0
   at System.Collections.Generic.Dictionary`2.TryInsert(TKey key, TValue value, InsertionBehavior behavior)
   at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value)

解决方案：检查被复制的行不可以出现合并单元格。