通过反射动态实填充实体类

第一种：检测整个实体类

using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Reflection;
using System.Data;

public partial class bangsotest_dr : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        IList<user> userlist;
        string sqlcmd = "select top 1000 Username,Password from userinfo order by id";//这里的Username和Password会根据实体类中的对应字段，自动填充或跳过
        using (SqlDataReader dr = Bangso.DBUtility.SQLHelper.ExecuteDataReader(sqlcmd))
        {
            userlist = FillEntityFromReader<user>(dr);
        }

        foreach (user u in userlist)
        {
            Response.Write(u.Username + "<br>");
        }
    }

    public static IList<T> FillEntityFromReader<T>(SqlDataReader reader)
    {
        List<T> list = new List<T>();
        List<PropertyInfo> pinfoList = new List<PropertyInfo>();
        Boolean checkedPropertyInfo = false;
        while (reader.Read())
        {
            T instance = Activator.CreateInstance<T>();

            #region 检查数据库字段与实体类属性的匹配情况
            if (!checkedPropertyInfo)
            {
                foreach (PropertyInfo pinfo in typeof(T).GetProperties())
                {
                    //判断reader是否有此Property中的BoundFieldAttribute所对应需要绑定的字段
                    if (reader.GetSchemaTable().Select("ColumnName='" + pinfo.Name + "'").Length > 0)
                    {
                        pinfoList.Add(pinfo);
                    }
                }
            }
            #endregion

            //查检完成
            checkedPropertyInfo = true;

            //开始赋值
            foreach (PropertyInfo info in pinfoList)
            {
                int index = reader.GetOrdinal(info.Name);
                if (reader.GetValue(index) != DBNull.Value)
                {
                    if (!info.PropertyType.IsEnum)
                    {
                        info.SetValue(instance, Convert.ChangeType(reader.GetValue(index), info.PropertyType), null);
                    }
                    else
                    {
                        info.SetValue(instance, Enum.Parse(info.PropertyType, reader.GetValue(index).ToString()), null);
                    }
                }
            }

            list.Add(instance);
        }
        reader.Close();
        return list;
    }

    public class user
    {
        string username;
        public string Username
        {
            get { return username; }
            set { username = value; }
        }
    }
}

 第二种根据实体类中的特性来选择填充哪些属性

using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Reflection;

public partial class bangsotest_dr : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        IList<user> userlist;
        string sqlcmd = "select top 100 username from userinfo";
        using (SqlDataReader dr = Bangso.DBUtility.SQLHelper.ExecuteDataReader(sqlcmd))
        {
            userlist = FillEntityFromReader<user>(dr);
        }

        foreach (user ui in userlist)
        {
            Response.Write(ui.Username + "<br>");
        }
    }

    public static IList<T> FillEntityFromReader<T>(SqlDataReader reader)
    {
        List<T> list = new List<T>();
        List<PropertyInfo> pinfoList = new List<PropertyInfo>();
        Boolean checkedPropertyInfo = false;
        while (reader.Read())
        {
            T instance = Activator.CreateInstance<T>();
            #region 检查数据库字段与实体类属性的匹配情况            if (!checkedPropertyInfo)
            {
                foreach (PropertyInfo pinfo in typeof(T).GetProperties())
                {
                    foreach (BoundFieldAttribute attr in pinfo.GetCustomAttributes(typeof(BoundFieldAttribute), true))
                    {
                        //判断reader是否有此Property中的BoundFieldAttribute所对应需要绑定的字段
                        if (reader.GetSchemaTable().Select("ColumnName='" + attr.FieldName + "'").Length > 0)
                        {
                            pinfoList.Add(pinfo);
                        }
                    }
                }
            }
            #endregion

            //查检完成
            checkedPropertyInfo = true;

            //开始赋值
            foreach (PropertyInfo info in pinfoList)
            {
                int index = reader.GetOrdinal(info.Name);
                if (reader.GetValue(index) != DBNull.Value)
                {
                    if (!info.PropertyType.IsEnum)
                    {
                        info.SetValue(instance, Convert.ChangeType(reader.GetValue(index), info.PropertyType), null);
                    }
                    else
                    {
                        info.SetValue(instance, Enum.Parse(info.PropertyType, reader.GetValue(index).ToString()), null);
                    }
                }
            }

            list.Add(instance);
        }
        return list;
    }

    public class BoundFieldAttribute : Attribute
    {
        private string fieldName;

        /// <summary>
        /// 指定绑定的数据库字段名
        /// </summary>
        public string FieldName
        {
            get { return fieldName; }
        }

        /// <summary>
        /// 初始化一个特性
        /// </summary>
        /// <param name="_fieldName">数据库字段名</param>
        public BoundFieldAttribute(string _fieldName)
        {
            this.fieldName = _fieldName;
        }
    }

    public class user
    {
        string username, password;
        [BoundFieldAttribute("Username")]//这里的特性声明一定要，否则将无法绑定
        public string Username
        {
            get { return username; }
            set { username = value; }
        }
        
        public string Password//这里的Password将不会被填充，因为它没有声明特性
        {
            get { return password; }
            set { password = value; }
        }
    }
}