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动态生成实体类

转载: .net 根据匿名类生成实体类，根据datatable生成实体类,根据sql生成实体类

在开发中可能会遇到这几种情况

1、EF或LINQ查询出来的匿名对象在其它地方调用不方便，又懒的手动建实体类

2、通过datatable反射实体需要先建一个类，头痛

3、通过SQL语句返回的实体也需要先建一个类，头痛

4、如果通过代码生成器要写模版，需要安装或者不想生成一堆不用的类

为了解决上面的不便之处，我封装了一个实体生成类，可以扔到程序里面任意调用

封装类：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Text.RegularExpressions;
 
namespace SyntacticSugar
{
    /// <summary>
    /// ** 描述：实体生成类
    /// ** 创始时间：2015-4-17
    /// ** 修改时间：-
    /// ** 作者：sunkaixuan
    /// ** qq：610262374 欢迎交流,共同提高 ,命名语法等写的不好的地方欢迎大家的给出宝贵建议
    /// </summary>
    public class ClassGenerating
    {
        /// <summary>
        /// 根据匿名类获取实体类的字符串
        /// </summary>
        /// <param name="entity">匿名对象</param>
        /// <param name="className">生成的类名</param>
        /// <returns></returns>
        public static string DynamicToClass(object entity, string className)
        {
            StringBuilder reval = new StringBuilder();
            StringBuilder propertiesValue = new StringBuilder();
            var propertiesObj = entity.GetType().GetProperties();
            string replaceGuid = Guid.NewGuid().ToString();
            string nullable = string.Empty;
            foreach (var r in propertiesObj)
            {
 
                var type = r.PropertyType;
                if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>))
                {
                    type = type.GetGenericArguments()[0];
                    nullable = "?";
                }
                if (!type.Namespace.Contains("System.Collections.Generic"))
                {
                    propertiesValue.AppendLine();
                    string typeName = ChangeType(type);
                    propertiesValue.AppendFormat("public {0}{3} {1} {2}", typeName, r.Name, "{get;set;}", nullable);
                    propertiesValue.AppendLine();
                }
            }
 
            reval.AppendFormat(@"
                 public class {0}{{
                        {1}
                 }}
            ", className, propertiesValue);
 
 
            return reval.ToString();
        }
  
 
        /// <summary>
        /// 根据DataTable获取实体类的字符串
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="className"></param>
        /// <returns></returns>
        public static string DataTableToClass(DataTable dt, string className)
        {
            StringBuilder reval = new StringBuilder();
            StringBuilder propertiesValue = new StringBuilder();
            string replaceGuid = Guid.NewGuid().ToString();
            foreach (DataColumn r in dt.Columns)
            {
                propertiesValue.AppendLine();
                string typeName = ChangeType(r.DataType);
                propertiesValue.AppendFormat("public {0} {1} {2}", typeName, r.ColumnName, "{get;set;}");
                propertiesValue.AppendLine();
            }
            reval.AppendFormat(@"
                 public class {0}{{
                        {1}
                 }}
            ", className, propertiesValue);
 
 
            return reval.ToString();
        }
 
        /// <summary>
        ///  根据SQL语句获取实体类的字符串
        /// </summary>
        /// <param name="sql">SQL语句</param>
        /// <param name="className">生成的类名</param>
        /// <param name="server">服务名</param>
        /// <param name="database">数据库名称</param>
        /// <param name="uid">账号</param>
        /// <param name="pwd">密码</param>
        /// <returns></returns>
        public static string SqlToClass(string sql, string className, string server, string database, string uid, string pwd)
        {
            using (SqlConnection conn = new SqlConnection(string.Format("server={0};uid={2};pwd={3};database={1}", server, database, uid, pwd)))
            {
                SqlCommand command = new SqlCommand();
                command.Connection = conn;
                command.CommandText = sql;
                DataTable dt = new DataTable();
                SqlDataAdapter sad = new SqlDataAdapter(command);
                sad.Fill(dt);
                var reval = DataTableToClass(dt, className);
                return reval;
            }
        }
        /// <summary>
        ///  根据SQL语句获取实体类的字符串
        /// </summary>
        /// <param name="sql">SQL语句</param>
        /// <param name="className">生成的类名</param>
        /// <param name="connName">webconfig的connectionStrings name</param>
        /// <returns></returns>
        public static string SqlToClass(string sql, string className, string connName)
        {
            string connstr = System.Configuration.ConfigurationManager.ConnectionStrings[connName].ToString();
            if (connstr.Contains("metadata"))//ef
                connstr = Regex.Match(connstr, @"connection string\=""(.+)""").Groups[1].Value;
            using (SqlConnection conn = new SqlConnection(connstr))
            {
                SqlCommand command = new SqlCommand();
                command.Connection = conn;
                command.CommandText = sql;
                DataTable dt = new DataTable();
                SqlDataAdapter sad = new SqlDataAdapter(command);
                sad.Fill(dt);
                var reval = DataTableToClass(dt, className);
                return reval;
            }
        }
        /// <summary>
        /// 匹配类型
        /// </summary>
        /// <param name="type"></param>
        /// <returns></returns>
        private static string ChangeType(Type type)
        {
            string typeName = type.Name;
            switch (typeName)
            {
                case "Int32": typeName = "int"; break;
                case "String": typeName = "string"; break;
            }
            return typeName;
        }
    }
}

调用如下：

           //通过匿名对象生成实体类
            var dynamicObj = new { id = 1, name = "小名", entity = new enityt1() };
           //注意：只能是单个实体不能传入 List<T> ,集合需要   List[0]
            string classCode = ClassGenerating.DynamicToClass(dynamicObj, "classDynamic");


            //通过datatable生成实体类
            DataTable dt = new DataTable();
            dt.Columns.Add("Id", typeof(int));
            dt.Columns.Add("Name");

            classCode = ClassGenerating.DataTableToClass(dt, "classTatabale");


            //通过sql语句生成实体类
            classCode = ClassGenerating.SqlToClass("select * from note", "Note", "127.0.0.1", "MyWork", "sa", "sasa"); 
            classCode = ClassGenerating.SqlToClass("select * from dbo.AccessoriesDetail", "AccessoriesDetail", "NFDEntities");//通过 config connstring名称

然后在调试状态把你需要的结果CTRL+C 然后去新建一个类CTRL+V