ASP.NET中实现根据匿名类、datatable、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