C# ASP.NET 公共函数

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Model 处理类

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

namespace ZCKJ.Common
{
    public class ModelHandler
    {
        /// <summary>
        ///     从 reader 对象中逐行读取记录并将记录转化为 T 类型的集合
        /// </summary>
        /// <typeparam name="T">目标类型参数</typeparam>
        /// <param name="reader">实现 IDataReader 接口的对象。</param>
        /// <returns>指定类型的对象集合。</returns>
        public static List<T> ConvertToObject<T>(IDataReader reader)
            where T : class
        {
            List<T> list = new List<T>();
            T obj = default(T);
            Type t = typeof(T);
            Assembly ass = t.Assembly;

            Dictionary<string, PropertyInfo> propertys = ModelHandler.GetFields<T>(reader);
            PropertyInfo p = null;
            if (reader != null)
            {
                while (reader.Read())
                {
                    obj = ass.CreateInstance(t.FullName) as T;
                    foreach (string key in propertys.Keys)
                    {
                        p = propertys[key];
                        p.SetValue(obj, ModelHandler.ChangeType(reader[key], p.PropertyType), null);
                    }
                    list.Add(obj);
                }
            }

            return list;
        }

        /// <summary>
        ///     从 DataTale 对象中逐行读取记录并将记录转化为 T 类型的集合
        /// </summary>
        /// <typeparam name="T">目标类型参数</typeparam>
        /// <param name="reader">DataTale 对象。</param>
        /// <returns>指定类型的对象集合。</returns>
        public static List<T> ConvertToObject<T>(DataTable table)
            where T : class
        {
            return table == null
                ? new List<T>()
                : ModelHandler.ConvertToObject<T>(table.CreateDataReader() as IDataReader);
        }

        /// <summary>
        ///     将数据转化为 type 类型
        /// </summary>
        /// <param name="value">要转化的值</param>
        /// <param name="type">目标类型</param>
        /// <returns>转化为目标类型的 Object 对象</returns>
        private static object ChangeType(object value, Type type)
        {
            if (type.FullName == typeof(string).FullName)
            {
                return Convert.ChangeType(Convert.IsDBNull(value) ? null : value, type);
            }
            else if (type.FullName == typeof(DateTime).FullName)
            {
                if (value != null && value != DBNull.Value)
                {
                    NullableConverter convertor = new NullableConverter(type);
                    return Convert.IsDBNull(value) ? null : convertor.ConvertFrom(value);
                }
                else
                {
                    return null;
                }

            }
            if (type.IsGenericType && type.GetGenericTypeDefinition().Equals(typeof(Nullable<>)))
            {
                NullableConverter convertor = new NullableConverter(type);
                return Convert.IsDBNull(value) ? null : convertor.ConvertFrom(value);
            }
            return value;
        }

        /// <summary>
        ///     获取reader存在并且在 T 类中包含同名可写属性的集合
        /// </summary>
        /// <param name="reader">
        ///     可写域的集合
        /// </param>
        /// <returns>
        ///     以属性名为键，PropertyInfo 为值得字典对象
        /// </returns>
        private static Dictionary<string, PropertyInfo> GetFields<T>(IDataReader reader)
        {
            Dictionary<string, PropertyInfo> result = new Dictionary<string, PropertyInfo>();
            int columnCount = reader.FieldCount;
            Type t = typeof(T);

            PropertyInfo[] properties = t.GetProperties();
            if (properties != null)
            {
                List<string> readerFields = new List<string>();
                for (int i = 0; i < columnCount; i++)
                {
                    readerFields.Add(reader.GetName(i));
                }
                //IEnumerable<PropertyInfo> resList =
                //    (from PropertyInfo prop in properties
                //     where prop.CanWrite && readerFields.Contains(prop.Name.ToUpper())
                //     select prop);
                IEnumerable<PropertyInfo> resList =
                    (from PropertyInfo prop in properties
                     where prop.CanWrite && readerFields.Contains(prop.Name)
                     select prop);
                foreach (PropertyInfo p in resList)
                {
                    result.Add(p.Name, p);
                }
            }
            return result;
        }
    }
}