Linq判断List<List<T>>中的重复项
导入Excel之前要检查一遍，看是否有重复的行等错误，多个模块有导入功能，我就想干脆写下面这样一个类，用来记录待导入文件中的错误：

C# code

    public class ImportLog    {        /// <summary>        /// Excel行号        /// </summary>        public int RowID { get; set; }        /// <summary>        /// 当前行中每个单元格的值        /// </summary>        public List<object> FieldList { get; set; }        /// <summary>        /// 是否包含错误        /// </summary>        public bool HasError { get; set; }        /// <summary>        /// 错误信息        /// </summary>        public string ErrorMsg { get; set; }    }

先拿“检查重复的行”来试试：

C# code

        public List<ImportLog> GetRepeatedRows(List<ImportLog> list = null)        {            if (list == null)            {                list = new List<ImportLog>()                {                    new ImportLog(){ RowID=1, FieldList=new List<object>(){"1","11","111"}, ErrorMsg=""},                    new ImportLog(){ RowID=2, FieldList=new List<object>(){"1","11","111"}, ErrorMsg=""},                    new ImportLog(){ RowID=3, FieldList=new List<object>(){"1","11","111","1111"}, ErrorMsg=""},                    new ImportLog(){ RowID=4, FieldList=new List<object>(){"1","11","111","1112"}, ErrorMsg=""},                    new ImportLog(){ RowID=5, FieldList=new List<object>(){"1","11","112","1121"}, ErrorMsg=""},                    new ImportLog(){ RowID=6, FieldList=new List<object>(){"1","11","112","1121"}, ErrorMsg=""},                    new ImportLog(){ RowID=7, FieldList=new List<object>(){"1","12","121","1211"}, ErrorMsg=""},                    new ImportLog(){ RowID=8, FieldList=new List<object>(){"1","12","122","1221"}, ErrorMsg=""},                    new ImportLog(){ RowID=9, FieldList=new List<object>(){"1","13","131","1311"}, ErrorMsg=""},                    new ImportLog(){ RowID=10, FieldList=new List<object>(){"2","21","211","2111"}, ErrorMsg=""},                    new ImportLog(){ RowID=11, FieldList=new List<object>(){"2","21","211","2111"}, ErrorMsg=""},                    new ImportLog(){ RowID=11, FieldList=new List<object>(){"2","21","211","2111"}, ErrorMsg=""},                };            }            //方式1：成功，但效率貌似不高            //var ret1 = list.FindAll(a => list.FindAll(b => b.FieldList.Intersect(a.FieldList).Count() == a.FieldList.Count).Count > 1);            //方式2：group by m.FieldList into g 失败            var ret2 = (from t in list                        where (                         from d in                             (                                 from m in list                                 group m by m.FieldList into g                                 where g.Count() > 1                                 select g                                 )                         select d.Key                        ).Contains(t.FieldList)                        select t).ToList();            var count = ret2.Count;//count=0 ……            return ret2;        }

各位大神，谁能给优化一下方式1，再给改改方式2？
拜谢！

呃，准备下班了，明天上午来了给分，见谅……

[解决办法]

C# code

var ret2=list.GroupBy(l=>string.Join(",",l.FieldList.OrderBy(x=>x).Select(x=>x.ToString()).ToArray()))             .Where(g=>g.Count()>1);
[解决办法]
我尝试也写了一个，不知道符不符合要求。

var result = list.GroupBy(L => L.RowID).Select(G => G.First()).ToList();