c# - convert a list of objects from one type to another using lambda expression

Question

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});
}

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

Answer 1

Try the following

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

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>.