EF大数据插入

_April给出代码：

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

namespace MMAS_Demo
{

    public class DbContextExtension
    {
        System.Data.Common.DbConnection Connection = null;

        public DbContextExtension(System.Data.Common.DbConnection connection)
        {
            Connection = connection;
        }

        public void BulkInsertAll<T>(IEnumerable<T> entities)  //大数据保存，针对一次插入几千条数据的情况
        {
            entities = entities.ToArray();

            string cs = Connection.ConnectionString;
            var conn = new SqlConnection(cs);
            conn.Open();

            Type t = typeof(T);

            var bulkCopy = new SqlBulkCopy(conn)
            {
                DestinationTableName = t.Name
            };

            var properties = t.GetProperties().Where(EventTypeFilter).ToArray();
            var table = new DataTable();

            foreach (var property in properties)
            {
                Type propertyType = property.PropertyType;
                if (propertyType.IsGenericType &&
                    propertyType.GetGenericTypeDefinition() == typeof(Nullable<>))
                {
                    propertyType = Nullable.GetUnderlyingType(propertyType);
                }

                table.Columns.Add(new DataColumn(property.Name, propertyType));
            }

            foreach (var entity in entities)
            {
                table.Rows.Add(properties.Select(
                  property => GetPropertyValue(
                  property.GetValue(entity, null))).ToArray());
            }

            bulkCopy.WriteToServer(table);
            conn.Close();
        }

        private bool EventTypeFilter(System.Reflection.PropertyInfo p)
        {
            var attribute = Attribute.GetCustomAttribute(p,
                typeof(AssociationAttribute)) as AssociationAttribute;

            if (attribute == null) return true;
            if (attribute.IsForeignKey == false) return true;

            return false;
        }

        private object GetPropertyValue(object o)
        {
            if (o == null)
                return DBNull.Value;
            return o;
        }
    }
}