AutoMapperExtension

　　安装AutoMapper.Data程序包后，AutoMap才有了IDataReader的映射扩展功能，并且在AutoMap初始化配置的时候添加配置IDataReader的映射，如下面所示代码中

  cfg.AddDataReaderMapping();

      以下所示代码全部在程序包AutoMapper 8.0.0版本以及AutoMapper.Data为3.0.0版本进行开发的，如代码复制到项目中出现异常信息，请注意检查版本信息。附程序包nuget安装命令

       install-package AutoMapper -version 8.0.0

       install-package AutoMapper.Data -version 3.0.0

    /// <summary>
    /// AutoMapper扩展
    /// </summary>
    public static class AutoMapperExtension
    {
        /// <summary>
        /// 创建Mapper
        /// </summary>
        /// <typeparam name="TSource">要被转化的model</typeparam>
        /// <typeparam name="TDestination">转化之后的model</typeparam>
        /// <returns></returns>
        private static IMapper CreateMapper<TSource, TDestination>()
        {
            var config = new MapperConfiguration(cfg =>
            {
                cfg.AddDataReaderMapping();
                cfg.CreateMap<TSource, TDestination>();
            }); ;
            var mapper = config.CreateMapper();
            return mapper;
        }

        /// <summary>
        /// 创建Mapper
        /// </summary>
        /// <param name="sourceType">要被转化的model类型</param>
        /// <param name="destinationType">转化之后的model类型</param>
        /// <returns></returns>
        private static IMapper CreateMapper(Type sourceType, Type destinationType)
        {
            var config = new MapperConfiguration(cfg => cfg.CreateMap(sourceType, destinationType)); ;
            var mapper = config.CreateMapper();
            return mapper;
        }

        /// <summary>
        /// 类型映射
        /// </summary>
        /// <typeparam name="TDestination">转化之后的model</typeparam>
        /// <param name="obj">可以使用这个扩展方法的类型</param>
        /// <returns>转化之后的实体</returns>
        public static TDestination MapTo<TDestination>(this object obj)
            where TDestination : class
        {
            var mapper = CreateMapper(obj.GetType(), typeof(TDestination));
            return mapper.Map<TDestination>(obj);
        }

        /// <summary>
        ///  类型映射
        /// </summary>
        /// <typeparam name="TDestination">转化之后的model</typeparam>
        /// <typeparam name="TSource">要被转化的model</typeparam>
        /// <param name="source">可以使用这个扩展方法的类型</param>
        /// <returns>转化之后的实体</returns>
        public static TDestination MapTo<TDestination, TSource>(this TSource source)
            where TDestination : class
            where TSource : class
        {
            if (source == null) return default(TDestination);
            var mapper = CreateMapper<TSource, TDestination>();
            return mapper.Map<TDestination>(source);
        }

        /// <summary>
        ///  类型映射,默认字段名字一一对应
        /// </summary>
        /// <typeparam name="TDestination">转化之后的model</typeparam>
        /// <typeparam name="TSource">要被转化的model</typeparam>
        /// <param name="source">可以使用这个扩展方法的类型</param>
        /// <returns>转化之后的实体</returns>
        public static List<TDestination> MapTo<TDestination>(this IEnumerable source)
            where TDestination : class
        {
            if (source == null) return default(List<TDestination>);
            var mapper = CreateMapper(source.AsQueryable().ElementType, typeof(TDestination));
            return mapper.Map<List<TDestination>>(source);
        }

        /// <summary>
        ///  类型映射
        /// </summary>
        /// <typeparam name="TDestination">转化之后的model</typeparam>
        /// <typeparam name="TSource">要被转化的model</typeparam>
        /// <param name="source">可以使用这个扩展方法的类型</param>
        /// <returns>转化之后的实体</returns>
        public static List<TDestination> MapTo<TDestination, TSource>(this IEnumerable<TSource> source)
            where TDestination : class
            where TSource : class
        {
            if (source == null) return default(List<TDestination>);
            var mapper = CreateMapper<TSource, TDestination>();
            return mapper.Map<List<TDestination>>(source);
        }

        /// <summary>
        /// DataTable映射
        /// </summary>
        /// <typeparam name="TDestination">转化之后的model</typeparam>
        /// <param name="dt">DataTable对象</param>
        /// <returns></returns>
        public static List<TDestination> MapTo<TDestination>(this DataTable dt)
            where TDestination : class
        {
            if (dt == null || dt.Rows.Count == 0) return default(List<TDestination>);
            var mapper = CreateMapper<IDataReader, TDestination>();
            return mapper.Map<List<TDestination>>(dt.CreateDataReader());
        }

        /// <summary>
        /// DataSet映射
        /// </summary>
        /// <typeparam name="TDestination">转化之后的model</typeparam>
        /// <param name="ds">DataSet对象</param>
        /// <param name="tableIndex">DataSet中要映射的DataTable的索引</param>
        /// <returns></returns>
        public static List<TDestination> MapTo<TDestination>(this DataSet ds, int tableIndex = 0)
           where TDestination : class
        {
            if (ds == null || ds.Tables.Count == 0 || ds.Tables[0].Rows.Count == 0) return default(List<TDestination>);
            var mapper = CreateMapper<IDataReader, TDestination>();
            return mapper.Map<List<TDestination>>(ds.Tables[tableIndex].CreateDataReader());
        }
    }