泛型 - 在List中的每个对象上调用一个方法<T>

Question

Is there a way to call a method on every object in a List - eg

Instead of

List<MyClass> items = setup();

foreach (MyClass item in items)
   item.SomeMethod();

You could do something like

foreach(items).SomeMethod();

Anything built in, extension methods, or am I just being too damn lazy?

Answer 1

Yes, on List<T> , there is:

items.ForEach(item => item.SomeMethod())

The oddity is that this is only available on List<T> , not IList<T> or IEnumerable<T>

To fix this, I like to add the following extension method:

public static class IEnumerableExtensions
{
    public static void ForEach<T>(this IEnumerable<T> items, Action<T> action)
    {
        foreach(var item in items)
            action(item);
    }
}

Then, you can use it on ANYTHING that implements IEnumerable<T> ... not just List<T>

Answer 2

items.ForEach(i => i.SomeMethod());

Answer 3

Lists have a ForEach method. You could also create an IEnumerable extension method, but it kind of goes against the spirit of Linq .

Answer 4

If you need to change a property on MyClass using MyMethod, use the 'Pipe' method from Jon Skeet's morelinq library

items = items.Pipe<MyClass>(i => i.Text = i.UpdateText()).ToList()

The possibilities are endless! :)