Linq 常用操作（增删改）

增加
using(var db = new Entities())
{
    //数据操作
    UserInfo user = new UserInfo()
    {
        UserName = "zhangsan1",
        UserPass = ""
    };
    db.UserInfo.Add(user);
    db.SaveChanges();
}

删除 先查询-再删除
using (var db = new Entities())
{
    var user = (from v in db.UserInfo
                where v.UserID ==
                select v).Single();
    db.UserInfo.Remove(user);
    db.SaveChanges();
}

修改单个实体 先查询-再修改
using (var db = new Entities())
{
    var user = (from v in db.UserInfo
                where v.UserName == "zhangsan"
                select v).Single();
    user.UserPass = "";
    db.SaveChanges();
}