EntityFramework数据持久化之EF的基本使用（增删查改）

首先，保证已经完成数据库以及Database First模式建模

增删查改

/// <summary>
/// 添加
/// </summary>
private static void Add()
{
    Admin admin = new Admin();
    admin.UName = Console.ReadLine();
    admin.Pwd = Console.ReadLine();
    using (MeixinEntities1 db=new MeixinEntities1())
    {
        db.Admin.Add(admin);
        db.SaveChanges();
        Console.WriteLine("管理员信息添加成功！");
    }
}

/// <summary>
/// 删除
/// </summary>
private static void Delete()
{
    Show();// 查询
    int id = Convert.ToInt32(Console.ReadLine());// 获取编号
    using (MeixinEntities1 db=new MeixinEntities1())
    {
        var data = db.Admin.FirstOrDefault(p => p.ID == id);
        db.Admin.Remove(data);
        db.SaveChanges();
    }
}

/// <summary>
/// 查询
/// </summary>
private static void Show()
{
    using (MeixinEntities1 db=new MeixinEntities1())
    {
        var data = db.Admin.ToList();
        foreach (var item in data)
        {
            Console.WriteLine("{0}\t{1}\t{2}\t",item.ID,item.UName,item.Pwd);
        }
    }
}

/// <summary>
/// 修改
/// </summary>
private static void Edit()
{
    Show();// 查询
    int id = Convert.ToInt32(Console.ReadLine());// 获取编号
    using (MeixinEntities1 db=new MeixinEntities1())
    {
        var data = db.Admin.FirstOrDefault(p => p.ID == id);
        if (data != null)// 判断id是否存在
        {
            string pwd = Console.ReadLine();
            if (!String.IsNullOrEmpty(pwd))
            {
                data.Pwd = pwd;
            }
        }
        db.SaveChanges();
    }
}

注：Using语句可自动释放数据库上下文对象占用的数据库资源

当然，这种增删查改是比较繁琐的，并且结构比较单一，下面介绍一种扩展的批量操作方法，还比较节省资源消耗

NuGet下载
Z.EntityFramework.Extensions
EntityFramework.Extended

/// <summary>
/// 添加多条信息
/// </summary>
private static void Show()
{
    using (MeixinEntities1 db = new MeixinEntities1())
    {
        var admins = new List<Admin>()
        {
            new Admin(){UName="zhangsan",Pwd="111"},
            new Admin(){UName="lisi",Pwd="111"},
            new Admin(){UName="wangwu",Pwd="111"},
            new Admin(){UName="zhaoliu",Pwd="111"}
        };
        db.BulkInsert(admins);
        db.SaveChanges();
    }
}
/// <summary>
/// 批量修改信息
/// </summary>
private static void Edit()
{
    using (MeixinEntities1 db = new MeixinEntities1())
    {
        Admin admin = new Admin();
        db.Admin.Update(p=> new Admin { Pwd="111"});
        db.SaveChanges();
    }
}

注意！！我这里只是测试案例，大家做项目切记切记别忘了where，更新和删除最为危险！！！