Question

I have two tables A and B. Their relation is 1:N.
I want to update one field in ALL the children tables, but I’m don’t know what LINQ expression to use to do that — shouldn’t be too difficult.

I was thinking something like:

parentEntity.childrens.All(..lambda expr..).field = value;

But obviously it’s not working.

I know the other option is a foreach(..), but I’d prefer L2E if possible.

Answer 1

You can’t set a property on all items of a collection without somehow looping through that collection, either with foreach, for, List<T>.ForEach, or similar.

If you want to keep it in one line, you could do something like:

author.Books.ToList().ForEach(b => b.PublishYear = 1999);