完美解决方案,可排除DATASET不支持System.Nullable错误

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Reflection;
using YTO.WeiXin.Model;
using System.Collections;

namespace YTO.WeiXin.Core
{
    public class ListToDataTable
    {
        public static DataTable ToDataTable<T>(IList<T> list)
        {
            return ToDataTable(list, null);
        }

        //将list转换成DataTable
        public static DataTable ToDataTable<T>(IList<T> list, params string[] propertyName)
        {
            List<string> propertyNameList = new List<string>();
            if (propertyName != null)
            {
                propertyNameList.AddRange(propertyName);
            }
            DataTable result = new DataTable();
            if (list.Count > 0)
            {
                PropertyInfo[] propertys = list[0].GetType().GetProperties();
                foreach (PropertyInfo pi in propertys)
                {
                    if (propertyNameList.Count == 0)
                    {
                        //if (DBNull.Value.Equals(pi.PropertyType))
                        //{
                        //   // pi.PropertyType = DateTime;
                        //}
                        Type colType = pi.PropertyType;
                        if (colType.IsGenericType && colType.GetGenericTypeDefinition() == typeof(Nullable<>))
                        {
                            colType = colType.GetGenericArguments()[0];
                        }
                        result.Columns.Add(pi.Name,colType);
                        //result.Columns.Add(pi.Name, pi.PropertyType);
                    }
                    else
                    {
                        if (propertyNameList.Contains(pi.Name))
                        {
                            result.Columns.Add(pi.Name, pi.PropertyType);
                        }
                    }
                }
                for (int i = 0; i < list.Count; i++)
                {
                    ArrayList tempList = new ArrayList();
                    foreach (PropertyInfo pi in propertys)
                    {
                        if (propertyNameList.Count == 0)
                        {
                            object obj = pi.GetValue(list[i], null);
                            tempList.Add(obj);
                        }
                        else
                        {
                            if (propertyNameList.Contains(pi.Name))
                            {
                                object obj = pi.GetValue(list[i], null);
                                tempList.Add(obj);
                            }
                        }
                    }
                    object[] array = tempList.ToArray();
                    result.LoadDataRow(array, true);
                }
            }
            return result;
        }