使用Linq 来解决Datatable 去除数据重复

在这也说明下，除此之外还可以通过 DataView 的方式来处理，当个人觉得这有点不好用。这里就不多作说明了

代码比较简单，直接看代码

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;

namespace DTS
{
    class Program
    {
        static void Main(string[] args)
        {
            DataTable _dt = new DataTable();
            _dt.Columns.Add("id", typeof(int));
            _dt.Columns.Add("name", typeof(string));
            _dt.Columns.Add("address", typeof(string));

            DataRow _dr = _dt.NewRow();
            _dr["id"] = ;
            _dr["name"] = "xiaodong";
            _dr["address"] = "beijing";
            _dt.Rows.Add(_dr);
            _dt.Rows.Add(_dr.ItemArray);
            _dt.Rows.Add(_dr.ItemArray);
            _dr = _dt.NewRow();

            _dr["id"] = ;
            _dr["name"] = "xiaodong";
            _dr["address"] = "shanghai";
            _dt.Rows.Add(_dr);
            _dr = _dt.NewRow();

            _dr["id"] = ;
            _dr["name"] = "xiaoming";
            _dr["address"] = "guangdong";
            _dt.Rows.Add(_dr);
            _dr = _dt.NewRow();

            _dr["id"] = ;
            _dr["name"] = "xudaxia";
            _dr["address"] = "fujian";
            _dt.Rows.Add(_dr);
            _dt.Rows.Add(_dr.ItemArray);
            Console.WriteLine("--------------------原来有重复数据的Table----------------------");
            _dt.AsEnumerable().ToList().ForEach(
                m=>
                {
                    Console.WriteLine(m["id"].ToString() + "   " + m["name"].ToString() + "  " + m["address"].ToString());
                });

            Console.WriteLine("--------------------去除重复后的Table----------------------");
            var _comPresult = _dt.AsEnumerable().Distinct(new DataTableRowCompare());
            DataTable _resultDt = _comPresult.CopyToDataTable();

            _resultDt.AsEnumerable().ToList().ForEach(
               x =>
               {
                   Console.WriteLine(x["id"].ToString() + "    " + x["name"].ToString() + "   " + x["address"].ToString());
               });
            Console.Read();
        }
        public class DataTableRowCompare : IEqualityComparer<DataRow>
        {

            #region IEqualityComparer<DataRow> 成员

            public bool Equals(DataRow x, DataRow y)
            {
                return ((x.Field<int>("id") == y.Field<int>("id") && x.Field<string>("name") == y.Field<string>("name") && x.Field<string>("address") == y.Field<string>("address")));
            }

            public int GetHashCode(DataRow obj)
            {
                return obj.ToString().GetHashCode();
            }

            #endregion
        }

    }
}

昨晚（2015-10-11）想了个对以上代码优化的办法，事比较多早上补上：

public static DataTable DistinctSomeColumn(DataTable sourceTable, params string[] fieldName)
{
    if (fieldName == null || fieldName.Length == ) return sourceTable;
    return sourceTable.AsEnumerable().Distinct(new ColumnEquals(fieldName)).CopyToDataTable();
}  

public class ColumnEquals : IEqualityComparer<DataRow>
{
    public ColumnEquals(string[] sArr)
    {
        _sArr = sArr;
    }  

    private string[] _sArr;  

    public bool Equals(DataRow x, DataRow y)
    {
        return !_sArr.Any(p => !x[p].Equals(y[p]));
    }  

    public int GetHashCode(DataRow dr)
    {
        return dr.ToString().GetHashCode();
    }
}