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

namespace Hncore.Infrastructure.Common
{
    public static class ListHelper<T>
    {
        #region 字符串转化为泛型集合

        /// <summary>
        /// 字符串转化为泛型集合
        /// </summary>
        /// <param name="str">字符串</param>
        /// <param name="splitstr">要分割的字符</param>
        /// <returns></returns>
        public static List<T> StrToList(string str, char splitstr)
        {
            List<T> list = new List<T>();
            if (string.IsNullOrEmpty(str))
            {
                return list;
            }
            if (!str.Contains(splitstr))
            {
                list.Add((T)Convert.ChangeType(str, typeof(T)));
                return list;
            }
            else
            {
                string[] strarray = str.Split(splitstr);

                foreach (string s in strarray)
                {
                    if (s != "")
                        list.Add((T)Convert.ChangeType(s, typeof(T)));
                }
                return list;
            }
        }

        /// <summary>
        /// 字符串转化为泛型集合
        /// </summary>
        /// <param name="str">字符串</param>
        /// <returns></returns>
        public static List<T> StrToList(string str)
        {
            return StrToList(str, ',');
        }

        #endregion

        public static string ListToStr(List<T> list, string splitstr=",")
        {
            string str = "";
            
            list.ForEach(t =>
            {
                str += t + splitstr;
            });

            if (str.EndsWith(splitstr))
            {
                str = str.Substring(0, str.Length - splitstr.Length);
            }

            return str;
        }

        #region 转换几个中所有元素的类型

        /// <summary>
        /// 转换几个中所有元素的类型
        /// </summary>
        /// <typeparam name="To"></typeparam>
        /// <param name="list"></param>
        /// <returns></returns>
        public static List<To> ConvertListType<To>(List<T> list)
        {
            if (list == null)
            {
                return null;
            }
            List<To> newlist = new List<To>();
            foreach (T t in list)
            {
                object to = new object();
                if (typeof(To).Name == "Guid")
                {
                    to = Guid.Parse(t.ToString());
                }
                else
                {
                    to = Convert.ChangeType(t, typeof(To));
                }
                newlist.Add((To)to);
            }
            return newlist;
        }

        #endregion

        #region 转化一个DataTable

        /// <summary>
        /// 转化一个DataTable
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="list"></param>
        /// <returns></returns>
        public static DataTable ToDataTable(IEnumerable<T> list)
        {
            //创建属性的集合
            List<PropertyInfo> pList = new List<PropertyInfo>();
            //获得反射的入口
            Type type = typeof(T);
            DataTable dt = new DataTable();
            //把所有的public属性加入到集合 并添加DataTable的列
            Array.ForEach(type.GetProperties(), p => { pList.Add(p); dt.Columns.Add(p.Name, p.PropertyType); });
            foreach (var item in list)
            {
                //创建一个DataRow实例
                DataRow row = dt.NewRow();
                //给row 赋值
                pList.ForEach(p => row[p.Name] = p.GetValue(item, null));
                //加入到DataTable
                dt.Rows.Add(row);
            }
            return dt;
        }

        #endregion

    }
}