dataList 是一个数组，而LINQ返回 IEnumerable< string> .在查询末尾添加 ToArray :

dataList is an array, while LINQ returns IEnumerable<string>. Add ToArray to the end of the query:

dataList = (from line in dataList
            let temp = from data in line.Split(';').ToList()
                        where line.Split(';').ToList().IndexOf(data) != 0 || line.Split(';').ToList().IndexOf(data) != 1
                        select data
            select string.Join(",", temp)).ToArray();