DataTable转换成IList(二)

作者：陈太汉

 

DataTable转换成IList(二)

 

DataTable转换成IList第一版出来之后，昨晚总是觉得有很多地方可以改进，所以今天一大早来就把它给修订了，当然还有一些地方可以改进，等我以后编码能力提高之后再出第三版吧，第二版应该够用

 

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Collections;
using System.Data;

namespace JSONTest
{
    public class TableToList<T> where T : new()
    {
        /// <summary>
        /// DataTable转换成IList
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public IList<T> ToList(DataTable dt)
        {
            if (dt == null || dt.Rows.Count == 0)
            {
                return null;
            }

            PropertyInfo[] properties = typeof(T).GetProperties();//获取实体类型的属性集合
            IList<string> colNames = GetColumnNames(dt.Columns);//按照属性顺序的列名集合
            List<T> list = new List<T>();
            T model = default(T);
            foreach (DataRow dr in dt.Rows)
            {
                model = new T();//创建实体
                int i = 0;
                foreach (PropertyInfo p in properties)
                {
                    if (p.PropertyType == typeof(string))
                    {
                        p.SetValue(model, dr[colNames[i++]], null);
                    }
                    else if (p.PropertyType == typeof(int))
                    {
                        p.SetValue(model, int.Parse(dr[colNames[i++]].ToString()), null);
                    }
                    else if (p.PropertyType == typeof(bool))
                    {
                        p.SetValue(model, bool.Parse(dr[colNames[i++]].ToString()), null);
                    }
                    else if (p.PropertyType == typeof(DateTime))
                    {
                        p.SetValue(model, DateTime.Parse(dr[colNames[i++]].ToString()), null);
                    }
                    else if (p.PropertyType == typeof(float))
                    {
                        p.SetValue(model, float.Parse(dr[colNames[i++]].ToString()), null);
                    }
                    else if (p.PropertyType == typeof(double))
                    {
                        p.SetValue(model, double.Parse(dr[colNames[i++]].ToString()), null);
                    }
                }
               
                list.Add(model);
            }

            return list;
        }

        /// <summary>
        /// 按照属性顺序的列名集合
        /// </summary>
        private IList<string> GetColumnNames(DataColumnCollection dcc)
        {
            PropertyInfo[] properties = typeof(T).GetProperties();//获取实体类型的属性集合

            //由于集合中的元素是确定的，所以可以指定元素的个数，系统就不会分配多余的空间，效率会高点
            IList<string> ilist = new List<string>(dcc.Count);
           
            foreach (PropertyInfo p in properties)
            {
                foreach (DataColumn dc in dcc)
                {
                    if (dc.ColumnName.ToLower().Contains(p.Name.ToLower()))
                    {
                        ilist.Add(dc.ColumnName);
                    }
                }
            }

            return ilist;
        }
 
    }
}