简单的方法来更新使用LINQ IEnumerable的对象 [英] Simple way to update IEnumerable objects using LINQ

问题描述

假设我有一个业务对象就是这样，

Assume I have a business object like this,

class Employee
    {
        public string name;
        public int id;
        public string desgination;
        public int grade;
    }

    List<Employee> lstEmp = new List<Employee>()
        {
            new Employee() { name="A",desgination="SE",id=1},
            new Employee() { name="b",desgination="TL",id=2},
            new Employee() { name="c",desgination="PL",id=3},
            new Employee() { name="d",desgination="SE",id=4},
            new Employee() { name="e",desgination="SSE",id=5},
        };

如果我想更新员工年级到3的名称是SE，那我也写这样的事情

And if I want to update the employee grade to 3 whose designation is "SE", then I have to write something like this

lstEmp=lstEmp.Select(x =>
            {
                x.grade = (x.desgination == "SE") ? 3 : x.grade;
                    return x;
            }).ToList();

但在这里使用时选择它会产生新的员工对象每次，而不是更新现有lstEmp，所以我有reassgin更新列表lstEmp。

But here when using select it will generate new employee object everytime, not updating the existing lstEmp, so I have to reassgin the updated list to lstEmp.

在我看来，频繁更新大量更新时，它会影响性能。对此有一个解决办法？

It seems to me it affects the performance when updating large updates frequently. Is there a workaround for this?

推荐答案

我相信默认LINQ方法doenst支持在线更新。但你可以创建自己的扩展方法才达到这个

I believe default LINQ methods doenst support inline updates. but you can create your own extension methods to achive this

  public static void Update<TSource>(this IEnumerable<TSource> outer, Action<TSource> updator)
        {
            foreach (var item in outer)
            {
                updator(item);
            }


        }

和使用像这样

 lstEmp.Update(x => x.grade = (x.desgination == "SE") ? 3 : x.grade);

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