c# 如何实现代码生成器

sing System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using personal_manage.Common.DAL;
using personal_manage.Common.dto;
using personal_manage.DAL.adapter;
using personal_manage.Models.entity;

namespace personal_manage.BLL.adapter
{
  public class DbBLL
  {
    public List<TableInfo> SelectTableList(CodeProjectDbConfigInfo codeProjectDbConfigInfo, string tableKeyword)
    {
      if (codeProjectDbConfigInfo.DbType == "Mysql" )
      {
       return DbAdapter.SelectTableNameByMySql(codeProjectDbConfigInfo.DbConnect, codeProjectDbConfigInfo.DbName, tableKeyword);
      }else if(codeProjectDbConfigInfo.DbType == "Oracle")
      {
        return DbAdapter.SelectTableNameByOracle(codeProjectDbConfigInfo.DbConnect, codeProjectDbConfigInfo.DbName, tableKeyword);
      }
      else if (codeProjectDbConfigInfo.DbType == "Sqlite")
      {
        return DbAdapter.SelectTableNameBySqlite(codeProjectDbConfigInfo.DbConnect, codeProjectDbConfigInfo.DbName, tableKeyword);
      }


      return null;
    }


    public List<TableFieldInfo> SelectTableFields(CodeProjectDbConfigInfo codeProjectDbConfigInfo, string tableName)
    {
      if (codeProjectDbConfigInfo.DbType == "Mysql")
      {
        return DbAdapter.SelectTableFieldsByMySql(codeProjectDbConfigInfo.DbConnect, codeProjectDbConfigInfo.DbName, tableName);
      }
      else if (codeProjectDbConfigInfo.DbType == "Oracle")
      {
        return DbAdapter.SelectTableFieldsByOracle(codeProjectDbConfigInfo.DbConnect, codeProjectDbConfigInfo.DbName, tableName);
      }
      else if (codeProjectDbConfigInfo.DbType == "Sqlite")
      {
        return DbAdapter.SelectTableFieldsBySqlite(codeProjectDbConfigInfo.DbConnect, codeProjectDbConfigInfo.DbName, tableName);
      }

      return null;
    }
  }
}