EF三層構架+介面實現（增刪改查）
阿新 • • 發佈：2018-12-12
DbContext
DbContext是EntityFramework很重要的部分，連線域模型與資料庫的橋樑，是與資料庫通訊的主要類。
DbContext主要負責以下活動：
EntitySet:：DbContext包含了所有對映到表的entities
Querying：將Linq-To-Entities轉譯為Sql併發送到資料庫
Change Tracking：從資料庫獲取entities後保留並跟蹤實體資料變化
Persisting Data：根據entity狀態執行Insert、update、delete命令
Caching：DbContext的預設第一級快取，在上下文中的生命週期中儲存entity
Manage Relationship：DbContext在DbFirst模式中使用CSDL、MSL、SSDL管理物件關係，Code first中使用fluent api 管理關係
增刪改查操作
IDAL
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using System.Threading.Tasks;
namespace ADO.NETEFDemo
{
public interface IDAL<T> where T : class,new()
{
/// <summary>
/// 增
/// </summary>
/// <param name="model"></param>
/// <returns></returns>
int Add(T model);
/// <summary>
/// 刪
/// </summary>
/// <param name="whereLambda"></param>
/// <returns></returns>
int Delete(Expression<Func<T, bool>> whereLambda);
/// <summary>
/// 改
/// </summary>
/// <param name="whereLambda"></param>
/// <param name="propertyNames"></param>
/// <param name="perpertyValues"></param>
/// <returns></returns>
int Update(Expression<Func<T, bool>> whereLambda, string[] propertyNames, object[] perpertyValues);
/// <summary>
/// 查
/// </summary>
/// <param name="whereLambda"></param>
/// <returns></returns>
List<T> GetModelList(Expression<Func<T, bool>> whereLambda);
}
}
DAL
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
namespace ADO.NETEFDemo
{
public class DAL<T> : IDAL<T> where T : class,new()
{
/// <summary>
/// 增
/// </summary>
/// <param name="model"></param>
/// <returns></returns>
public int Add(T model)
{
using (testbakEntities db = new testbakEntities())
{
db.Set<T>().Add(model);
return db.SaveChanges();
}
}
/// <summary>
/// 刪
/// </summary>
/// <param name="whereLambda"></param>
/// <returns></returns>
public int Delete(Expression<Func<T, bool>> whereLambda)
{
using (testbakEntities db = new testbakEntities())
{
var dbQuery = db.Set<T>();
//先查詢 對應表的 集合
var list = dbQuery.Where(whereLambda).ToList();
//遍歷集合 裡要刪除的元素
foreach (var item in list)
{
//標記為 刪除狀態
dbQuery.Remove(item);
}
return db.SaveChanges();
}
}
/// <summary>
/// 改
/// </summary>
/// <param name="whereLambda"></param>
/// <param name="propertyNames"></param>
/// <param name="perpertyValues"></param>
/// <returns></returns>
public int Update(Expression<Func<T, bool>> whereLambda, string[] propertyNames, object[] perpertyValues)
{
using (testbakEntities db = new testbakEntities())
{
//1、查詢要修改的物件集合
var list = db.Set<T>().Where<T>(whereLambda).ToList();
//2、獲取要修改的物件的型別
Type t = typeof(T);
//3、迴圈要修改的實體物件，並根據要修改的屬性名修改物件對應的屬性值
foreach (var item in list)
{
//迴圈 要修改的屬性 名稱， 並 反射取出 t 中的 屬性物件
for (int index = 0; index < propertyNames.Length; index++)
{
//獲取要修改的屬性名
string pName = propertyNames[index];
//獲取屬性物件
PropertyInfo pi = t.GetProperty(pName);
//呼叫屬性物件的 SetValue方法 為當前迴圈的 item物件 對應的屬性賦值
pi.SetValue(item, perpertyValues[index], null);
}
}
return db.SaveChanges();
}
}
/// <summary>
/// 查
/// </summary>
/// <param name="whereLambda"></param>
/// <returns></returns>
public List<T> GetModelList(Expression<Func<T, bool>> whereLambda)
{
using (testbakEntities db = new testbakEntities())
{
return db.Set<T>().Where(whereLambda).ToList();
}
}
}
}
BLL
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using System.Threading.Tasks;
namespace ADO.NETEFDemo
{
public static class BLL<T> where T : class,new()
{
private static IDAL<T> dal = new DAL<T>();
/// <summary>
/// 新增
/// </summary>
/// <param name="model"></param>
public static int Add(T model)
{
return dal.Add(model);
}
/// <summary>
/// 刪除
/// </summary>
/// <param name="whereLambda"></param>
public static int Delete(Expression<Func<T, bool>> whereLambda)
{
return dal.Delete(whereLambda);
}
/// <summary>
/// 修改
/// </summary>
/// <param name="whereLambda"></param>
/// <param name="propertyNames"></param>
/// <param name="perpertyValues"></param>
/// <returns></returns>
public static int Update(Expression<Func<T, bool>> whereLambda, string[] propertyNames, object[] perpertyValues)
{
return dal.Update(whereLambda, propertyNames, perpertyValues);
}
/// <summary>
/// 查詢
/// </summary>
/// <param name="whereLambda"></param>
/// <returns></returns>
public static List<T> GetModelList(Expression<Func<T, bool>> whereLambda)
{
return dal.GetModelList(whereLambda);
}
}
}
呼叫
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ADO.NETEFDemo
{
class Program
{
static void Main(string[] args)
{
GetArticleList();
AddArticle();
GetArticleList();
UpdateArticle();
GetArticleList();
DeleteArticel();
GetArticleList();
Console.ReadKey();
}
/// <summary>
/// 更新
/// </summary>
private static void UpdateArticle()
{
int result = BLL<t_crobot_reship_articles>
.Update(e => e.title.Contains("EF"), new[] { "title", "update_time" },
new object[] { "我是使用EF修改過標題的文章", DateTime.Now });
if (result >= 0)
{
Console.WriteLine("更新成功");
}
else
{
Console.WriteLine("更新失敗");
}
Console.WriteLine();
}
/// <summary>
/// 刪除
/// </summary>
private static void DeleteArticel()
{
int result = BLL<t_crobot_reship_articles>.Delete(e => e.title.Contains("EF"));
if (result >= 0)
{
Console.WriteLine("刪除成功");
}
else
{
Console.WriteLine("刪除失敗");
}
Console.WriteLine();
}
/// <summary>
/// 新增
/// </summary>
private static void AddArticle()
{
t_crobot_reship_articles model = new t_crobot_reship_articles();
model.create_time = DateTime.Now;
model.module_id = 1;
model.adword_id = 20;
model.pick_id = 1;
model.vote_id = "1";
model.title = "我是使用EF新增的文章";
model.content_id = 1;
model.release_url = "http://www.sss.com";
model.state = true;
int result = BLL<t_crobot_reship_articles>.Add(model);
if (result >= 0)
{
Console.WriteLine("新增成功");
}
else
{
Console.WriteLine("新增失敗");
}
Console.WriteLine();
}
/// <summary>
/// 獲取文章列表
/// </summary>
private static void GetArticleList()
{
List<t_crobot_reship_articles> articleList = BLL<t_crobot_reship_articles>
.GetModelList(e => e.state == true);
Console.WriteLine("文章總數：" + articleList.Count.ToString());
foreach (t_crobot_reship_articles model in articleList)
{
Console.WriteLine("標題：" + model.title);
}
Console.WriteLine();
}
}
}
結果
