C# - 通过自定义注解反射生成SQL语句[转]

转自http://blog.163.com/jong_cai/blog/static/87028045200902033553581/

----------------------------------------Program.cs----------------------------------------

using System;
using System.Collections.Generic;
using System.Text;
//反射命名空间
using System.Reflection;
namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            Student stu = new Student(1, "Jong_Cai", 21);
            Insert(stu);
        }

public static void Insert(Object obj)
        {
            String fileds = null;
            String values = null;

Type type = obj.GetType();
            //获取类名
            String className = type.Name;
            //获取所有公有属性
            PropertyInfo[] info = type.GetProperties();

foreach (PropertyInfo var in info)
            {
                //取得属性的特性标签，false表示不获取因为继承而得到的标签
                Object[] attr = var.GetCustomAttributes(false);
                if (attr.Length > 0)
                {
                    //从注解数组中取第一个注解(一个属性可以包含多个注解)
                    MyAttribute myattr = attr[0] as MyAttribute;
                    if (myattr.PrimaryKey == true)
                    {
                        continue;
                    }
                }
                fileds += var.Name + ",";
                values += "'" + var.GetValue(obj, null) + "',";
            }

fileds = fileds.Substring(0, fileds.Length - 1);
            values = values.Substring(0, values.Length - 1);
            String sql = "insert into {0}({1}) values({2})";
            sql = String.Format(sql, className, fileds, values);
            Console.WriteLine(sql);
        }
    }
}

-----------------------------------------------MyAttribute.cs---------------------------------------------------

using System;
using System.Collections.Generic;
using System.Text;

namespace Test
{
    //自定义注解类
    class MyAttribute: Attribute
    {
        public Boolean PrimaryKey = false;
        public String Type = null;
    }
}

-------------------------------------------Student.cs--------------------------------------------

using System;
using System.Collections.Generic;
using System.Text;

namespace Test
{
    public class Student
    {
        private int _id;
        [My(PrimaryKey = true, Type = "自动增长")] //自定义注解
        public int Id
        {
            get { return _id; }
            set { _id = value; }
        }

private String _name;
        [My(PrimaryKey = false, Type = "名字")] //自定义注解
        public String Name
        {
            get { return _name; }
            set { _name = value; }
        }

private int _age;
        [My(PrimaryKey = false, Type = "年龄")] //自定义注解
        public int Age
        {
            get { return _age; }
            set { _age = value; }
        }

public Student(int id, String name, int age)
        {
            this._id = id;
            this._name = name;
            this._age = age;
        }
    }
}