ASP.NET中實現根據匿名類、datatable、sql生成實體類

在開發中可能會遇到這幾種情況：

1、EF或LINQ查詢出來的匿名對象在其它地方調用不方便，又懶的手動建實體類

2、通過datatable反射實體需要先建一個類 ，頭痛

3、通過SQL語句返回的實體也需要先建一個類 ，頭痛

4、如果通過代碼生成器要寫模版，需要安裝或者不想生成一堆不用的類 
 
為了解決上面的不便之處，我封裝了一個實體生成類，可以扔到程序裡面任意調用

封裝類：

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：實體生成類
  /// ** 創始時間：2015-4-17
  /// ** 修改時間：-
  /// ** 作者：sunkaixuan
  /// ** qq：610262374 歡迎交流,共同提高 ,命名語法等寫的不好的地方歡迎大家的給出寶貴建議
  /// </summary>
  public class ClassGenerating
  {
    /// <summary>
    /// 根據匿名類獲取實體類的字符串
    /// </summary>
    /// <param name="entity">匿名對象</param>
    /// <param name="className">生成的類名</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>
    /// 根據DataTable獲取實體類的字符串
    /// </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>
    /// 根據SQL語句獲取實體類的字符串
    /// </summary>
    /// <param name="sql">SQL語句</param>
    /// <param name="className">生成的類名</param>
    /// <param name="server">服務名</param>
    /// <param name="database">數據庫名稱</param>
    /// <param name="uid">賬號</param>
    /// <param name="pwd">密碼</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>
    /// 根據SQL語句獲取實體類的字符串
    /// </summary>
    /// <param name="sql">SQL語句</param>
    /// <param name="className">生成的類名</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>
    /// 匹配類型
    /// </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;
    }
  }
}

調用如下：

//通過匿名對象生成實體類
      var dynamicObj = new { id = 1, name = "小名", entity = new enityt1() };
      //注意：只能是單個實體不能傳入 List<T> ,集合需要  List[0]
      string classCode = ClassGenerating.DynamicToClass(dynamicObj, "classDynamic");


      //通過datatable生成實體類
      DataTable dt = new DataTable();
      dt.Columns.Add("Id", typeof(int));
      dt.Columns.Add("Name");

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


      //通過sql語句生成實體類
      classCode = ClassGenerating.SqlToClass("select * from note", "Note", "127.0.0.1", "MyWork", "sa", "sasa"); 
      classCode = ClassGenerating.SqlToClass("select * from dbo.AccessoriesDetail", "AccessoriesDetail", "NFDEntities");//通過 config connstring名稱

然後在調試狀態把你需要的結果CTRL+C 然後去新建一個類CTRL+V