C# 反射之SqlDatareader转换为Model实体.

虽说反射的效率比较低,但是在当今的时代,盛行的大数据,以及高并发的产生,硬件的产能正在逐渐的提升,所以我们可以用空间来换取时间.反射所消耗的那些性能问题其实在企业级开发而言也就无所谓了.二 : 反射得确是可以提升开发效率.

将SqlDataReader反射转换为Model实体,省去了每个Reader还要判断转换一下,如此消耗开发效率的问题,怎么能容忍呢?

代码 : 

        /// <summary>
        ///   将SqlDataReader转换为Model实体
        /// </summary>
        /// <typeparam name="T">实例类名</typeparam>
        /// <param name="dr">Reader对象</param>
        /// <returns>实体对象</returns>
        public static T ReaderToModel<T>(IDataReader dr)
        {
            try
            {
                using (dr)
                {
                    if (dr.Read())
                    {
                        Type modelType = typeof(T);
                        T model = Activator.CreateInstance<T>();
                        for (int i = 0; i < dr.FieldCount; i++)
                        {
                            if(!IsNullOrDbNull(dr[i]))
                            {
                                PropertyInfo pi = modelType.GetProperty(GetPropertyName(dr.GetName(i)));
                                pi.SetValue(model, HackType(dr[i], pi.PropertyType), null);
                            } 
                        }
                        return model;
                    }
                }
                return default(T);
            }
            catch (Exception)
            {

                throw;
            }
        } 

        /// <summary>
        ///  对可空类型进行判断.
        /// </summary> 
        private static object HackType(object value, Type conversionType)
        {
            if (conversionType.IsGenericType && conversionType.GetGenericTypeDefinition().Equals(typeof(Nullable<>)))
            {
                if (value == null)
                {
                    return null;
                }
                System.ComponentModel.NullableConverter nullAbleConverter = new System.ComponentModel.NullableConverter(conversionType);
                conversionType = nullAbleConverter.UnderlyingType;
            }
            return Convert.ChangeType(value, conversionType);
        }

        /// <summary>
        ///  判断字段值是否为NUll
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        private static bool IsNullOrDbNull(object obj)
        {
            return ((obj is DBNull) || string.IsNullOrEmpty(obj.ToString())) ? true : false;
        }

        /// <summary>
        ///  获取属性类的名称
        /// </summary>
        /// <param name="column">列名</param>
        /// <returns>列名</returns>
        private static string GetPropertyName(string column)
        { 
            string[] narr = column.Split('_');
            column = "";
            for (int i = 0; i < narr.Length; i++)
            {
                if (narr[i].Length > 1)
                {
                    column += narr[i].Substring(0, 1).ToUpper() + narr[i].Substring(1);
                }
                else
                {
                    column += narr[i].Substring(0, 1).ToUpper();
                }
            }
            return column;
        }