DataTable,List去重复记录的方法

List<OUTP_DRUGITEM> LDrugitem_all = query1.ToList(); OrderDrugitem_yp = LDrugitem_all.Distinct(new Comparint()).ToList();//DISTINCT /// <summary> /// LINQEntityDistinct显示字段唯一值记录 /// </summary> internal class Comparint : IEqualityComparer<OUTP_DRUGITEM> { public bool Equals(OUTP_DRUGITEM x, OUTP_DRUGITEM y) { if (x == null && y == null) return false; return (x.IDM == y.IDM); } public int GetHashCode(OUTP_DRUGITEM obj) { return obj.ToString().GetHashCode(); } }

List去重复记录的方法

 

 

using System.Collections.Generic; using System.Linq; using System.Data; using System; namespace ConsoleApplication2 { class Program { static void Main(string[] args) { DataTable tbl = new DataTable(); tbl.Columns.Add("Id", typeof(System.Int32)); tbl.Columns.Add("City", typeof(System.String)); tbl.Columns.Add("Province", typeof(System.String)); tbl.Rows.Add(1, "武汉", "湖北"); tbl.Rows.Add(2, "应城", "湖北"); tbl.Rows.Add(3, "武汉", "湖北"); IEnumerable <DataRow> r = tbl.AsEnumerable().Distinct(new CityComparer()); //到这一步,r里就是去重复的记录了 foreach (var item in r) { Console.WriteLine(item["Id"] + "，" + item["City"] + "，" + item["Province"]); } Console.ReadLine(); } } class CityComparer : IEqualityComparer <DataRow> { public bool Equals(DataRow r1, DataRow r2) { return r1["City"] == r2["City"]; } public int GetHashCode(DataRow obj) { return obj.ToString().GetHashCode(); } } }

 

上面的代码，将DataTable中"城市名"重复的记录去掉了

 

 

如何去掉DataTable里重复的记录(DataTable是返回过来的，不能再重新查询数据库，所以无法用sql中的select distinct xxx处理，只能在DataTable上动脑筋) 

思路：将DataTable转成IEnumerable，然后就能调用Distinct方法了