using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;

namespace DAL
{
    /// <summary>
    /// 雷怡 2021-08-17
    /// TableData List 互转
    /// </summary>
    public static class DTList
    {
        /// <summary>
        /// DataTable转换成List<T>
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="table"></param>
        /// <returns></returns>
        public static List<T> ConvertToList<T>(DataTable table)
        {
            List<T> list = new List<T>();
            T t = default(T);
            PropertyInfo[] propertypes = null;
            string tempName = string.Empty;
            foreach (DataRow row in table.Rows)
            {
                t = Activator.CreateInstance<T>();
                propertypes = t.GetType().GetProperties();
                foreach (PropertyInfo pro in propertypes)
                {
                    tempName = pro.Name;
                    if (table.Columns.Contains(tempName))
                    {
                        object value = row[tempName];
                        if (!value.ToString().Equals(""))
                        {
                            pro.SetValue(t, value, null);
                        }
                    }
                }
                list.Add(t);
            }
            return list.Count == 0 ? null : list;
        }

        /// <summary>
        /// List<T>转换成DataTable  
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="list">实例化当前list<T> 的list集合</param>
        /// <param name="dataList">集合数据</param>
        /// <returns>返回DataTable</returns>
        public static System.Data.DataTable ToDataTable<T>(this System.Collections.Generic.IList<T> list, System.Collections.Generic.IList<T> dataList) where T : class, new()
        {
            if (dataList == null || !dataList.Any())
            {
                return null;
            }
            Type type = typeof(T);
            System.Data.DataTable dt = new System.Data.DataTable(type.Name);
            System.Reflection.PropertyInfo[] propertyInfoArray = type.GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance);
            foreach (T t in dataList.Where(t => t != null))
            {
                System.Data.DataRow row = dt.NewRow();
                for (int i = 0, j = propertyInfoArray.Length; i < j; i++)
                {
                    System.Reflection.PropertyInfo propertyInfo = propertyInfoArray[i];
                    string name = propertyInfo.Name;
                    if (dt.Columns[name] == null)
                    {
                        System.Data.DataColumn column = new System.Data.DataColumn(name, propertyInfo.PropertyType);
                        dt.Columns.Add(column);
                    }
                    row[name] = propertyInfo.GetValue(t, null);
                }
                dt.Rows.Add(row);
            }
            return dt;
        }

    }
}