使用 lambda 表达式将对象列表从一种类型转换为另一种类型 [英] convert a list of objects from one type to another using lambda expression

问题描述

我有一个 foreach 循环读取一种类型的对象列表并生成不同类型的对象列表.有人告诉我 lambda 表达式可以达到相同的结果.

I have a foreach loop reading a list of objects of one type and producing a list of objects of a different type. I was told that a lambda expression can achieve the same result.

var origList = List<OrigType>(); // assume populated
var targetList = List<TargetType>(); 

foreach(OrigType a in origList) {
    targetList.Add(new TargetType() {SomeValue = a.SomeValue});
}

任何帮助将不胜感激 - 我是 lambda 和 linq 的新手谢谢，

Any help would be appreciated- i'm new to lambda and linq thanks, s

推荐答案

尝试以下方法

var targetList = origList
  .Select(x => new TargetType() { SomeValue = x.SomeValue })
  .ToList();

这是结合使用 Lambdas 和 LINQ 来实现的解决方案.Select 函数是一种投影样式方法，它将传入的委托(在本例中为 lambda)应用于原始集合中的每个值.结果将在新的 IEnumerable 中返回..ToList 调用是一个扩展方法，它将把这个 IEnumerable 转换成一个 List.

This is using a combination of Lambdas and LINQ to achieve the solution. The Select function is a projection style method which will apply the passed in delegate (or lambda in this case) to every value in the original collection. The result will be returned in a new IEnumerable<TargetType>. The .ToList call is an extension method which will convert this IEnumerable<TargetType> into a List<TargetType>.

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