c# - 查询以检测重复行

Question

我已经使用 c# 将 XML 文件中的数据读取到 DataSet 中，而不是想识别该集中的重复（完全相同）行。我尝试了这种分组，并且有效！

var d= from r1 in table.AsEnumerable()
       group r1 by new
       {
            t0 = r1[0],
            t1 = r1[1],
            t2 = r1[2],
            t3 = r1[3],
            t4 = r1[4],
            t5 = r1[5],
            t6 = r1[6],
            t7 = r1[7],
            t8 = r1[8],
       }
       into grp
       where grp.Count() > 1
       select grp;

但是数据列的数量可以不同，所以我不能像上面那样在查询中应用静态分组。我必须动态生成分组数组？

我不想删除重复的，我只想找到它们！

Answer 1

var rows = table.AsEnumerable();
var unique = rows.Distinct(DataRowComparer.Default);
var duplicates = rows.Except(unique); // , DataRowComparer.Default);

Answer 2

试试这个

DataTable dt = TableName;
dt = oPerformance.RemoveDuplicateRows(dt, ColToCompareAndRemove);

这是函数 RemoveDuplicateRows

public DataTable RemoveDuplicateRows(DataTable dTable, string colName)
        {
            Hashtable hTable = new Hashtable();
            ArrayList duplicateList = new ArrayList();

            //Add list of all the unique item value to hashtable, which stores combination of key, value pair.
            //And add duplicate item value in arraylist.
            foreach (DataRow drow in dTable.Rows)
            {
                if (hTable.Contains(drow[colName]))
                    duplicateList.Add(drow);
                else
                    hTable.Add(drow[colName], string.Empty);
            }

            //Removing a list of duplicate items from datatable.
            foreach (DataRow dRow in duplicateList)
                dTable.Rows.Remove(dRow);

            //Datatable which contains unique records will be return as output.
            return dTable;
        }