EF实现增删改查

最新推荐文章于 2022-07-15 15:28:55 发布

changuncle

最新推荐文章于 2022-07-15 15:28:55 发布

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分类专栏： MVC+EF 文章标签： mvc string EF 增删改查

本文链接：https://blog.youkuaiyun.com/xiaouncle/article/details/53471331

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本文详细介绍了一种经典的Web开发模式MVC结合Entity Framework的实际应用案例，包括数据查询、添加、修改及删除等核心操作，并提供了具体的代码实现。

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MVC+EF这一组合早就火遍大江南北了，现在有点快过气了。我没正点赶上二路汽车，就当做驴车过来的吧，重新回顾一下它们的用法，记录下来。

查询

public ActionResult Index(string Id)
{
    using (TestContext testContext = new TestContext())
    {
        int id = string.IsNullOrEmpty(Id) ? 2 : int.Parse(Id);
        //查询方法一
        //UserInfo userInfo = (from u in testContext.UserInfo where u.Id == id select u).FirstOrDefault();
        //查询方法二
        UserInfo userInfo = testContext.UserInfo.FirstOrDefault(a => a.Id == id);
        if (userInfo == null)
        {
            return View();
        }
        UserInfoModel model = new UserInfoModel()
        {
            Id = userInfo.Id,
            UserId = userInfo.UserId,
            UserName = userInfo.UserName,
            AddTime = userInfo.AddTime,
            Gender = userInfo.Gender
        };
        return View(model);
    }
}

添加

[HttpPost]
public void Add(UserInfoModel model)
{
    using (TestContext testContext = new TestContext())
    {
        UserInfo userInfo = new UserInfo()
        {
            Id = model.Id,
            UserId = model.UserId,
            UserName = model.UserName,
            AddTime = model.AddTime,
            Gender = model.Gender
        };
        testContext.UserInfo.Add(userInfo);
        //调用SaveChanges()才会执行Sql操作
        testContext.SaveChanges();
        //id值为自增主键的值
        int id = userInfo.Id;
        Index(id.ToString());
    }            
}

修改
无论是修改或是删除都需要先查询到对应的数据，然后再进行其他操作。

[HttpPost]
public void Edit(UserInfoModel model)
{
    using (TestContext testContext = new TestContext())
    {
        UserInfo userInfo = (from u in testContext.UserInfo where u.Id == model.Id select u).FirstOrDefault();
        userInfo.UserId = model.UserId;
        userInfo.UserName = model.UserName;
        userInfo.AddTime = model.AddTime;
        userInfo.Gender = model.Gender;
        testContext.SaveChanges();
    }
    Index(model.Id.ToString());
}

删除

[HttpPost]
public void Remove(UserInfoModel model)
{
    using (TestContext testContext = new TestContext())
    {
        UserInfo userInfo = (from u in testContext.UserInfo where u.Id == model.Id select u).FirstOrDefault();
        testContext.UserInfo.Remove(userInfo);
        testContext.SaveChanges();
    }
    Index(model.Id.ToString());
}

EF中使用Sql语句操作数据库

public string Delete(int Id)
{
    try
    {
        TestContext testContext = new TestContext();
        testContext.ExecuteStoreCommand(
            string.Format("delete from UserInfo where Id = {0} " ,Id));
        testContext.ExecuteStoreCommand("delete from UserInfo where Id=@Id and UserName=@UserName",new SqlParameter("@Id", 100),new SqlParameter("@UserName","果果修改"));
        testContext.Dispose();
        return "Success";
    }
    catch
    {
        return "Fail";
    }
}