如何将一个通过LINQ查找出来并重新构造的匿名对象转化成DATATABLE

最新推荐文章于 2021-12-08 23:06:21 发布

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最新推荐文章于 2021-12-08 23:06:21 发布

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原文链接：http://www.cnblogs.com/lilikang/archive/2008/10/21/1316212.html

本文介绍了一种使用LINQ查询表达式从对象集合中筛选数据，并将筛选结果转换为DataTable的方法。通过具体的代码示例，展示了如何自定义扩展方法实现这一过程。

如题：
DataTable resulttable=null;
IQueryable <DataRow> result=from table in tabledata
where table.field1='0215'
select new {字段1=table.field2+"-"+table.field4,字段2=table.field3};
resulttable = result.CopyToDataTable <DataRow>();

如上代码，但是转化出错，要如何转化?

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

namespace Test
{
    public class People
    {
        public string Name{get ;set;}
        public string City { get; set; }
        public string Sex { get; set; }
    }

    public static class Extension
    {
        public static DataTable CopyToDataTable<T>(this IEnumerable<T> array)
        {
            var ret = new DataTable();
            foreach (PropertyDescriptor dp in TypeDescriptor.GetProperties(typeof(T)))
               // if (!dp.IsReadOnly)
                    ret.Columns.Add(dp.Name, dp.PropertyType);
            foreach (T item in array)
            {
                var Row = ret.NewRow();
                foreach (PropertyDescriptor dp in TypeDescriptor.GetProperties(typeof(T)))
                   // if (!dp.IsReadOnly)
                        Row[dp.Name] = dp.GetValue(item);
                ret.Rows.Add(Row);
            }
            return ret;
        }

    }


    public class Linq2DataTable
    {
        private static List<People> GetData()
        {
            List<People> list = new List<People>();
            list.Add(new People {Name="Bruce",City ="SZ",Sex ="Man"});
            list.Add(new People { Name = "John", City = "GZ", Sex = "Man" });
            list.Add(new People { Name = "Judy", City = "CS", Sex = "Woman" });
            return list;
        }

        public static void Test()
        {
            List<People> data= GetData();
            var result = from p in data where p.Sex == "Man" select  new { Name = p.Name, City = p.City };
            DataTable dt = Extension.CopyToDataTable(result);
            Console.WriteLine(ToString(dt));
        }

        public static string ToString(System.Data.DataTable data)
        {
            StringBuilder sb = new StringBuilder();
            int colCount = data.Columns.Count;
            foreach (System.Data.DataRow dr in data.Rows)
            {
                for (int i = 0; i < colCount; i++)
                {
                    string s = (dr[i] == null ? string.Empty : dr[i].ToString());
                    sb.Append(s);
                    sb.Append(",");
                }
                sb.AppendLine();
            }
            return sb.ToString();
        }
    }
}

转载于:https://www.cnblogs.com/lilikang/archive/2008/10/21/1316212.html