Is it possible to recreate this statement without using a foreach?

Question

Possible Duplicate:
C#: Is operator for Generic Types with inheritance

Is it possible to add a list into another list whilst changing class type from Deal to DealBookmarkWrapper without using the foreach statement?

var list = new List<IBookmarkWrapper>();
foreach (var deal in deals)
{
    list.Add(new DealBookmarkWrapper(deal));
}

Thanks.

Justin Niessner · Accepted Answer · 2012-09-17T14:40:29.797

9

If you want the exact equivalent:

var list = deals.Select(d => new DealBookmarkWrapper(d))
                .Cast<IBookmarkWrapper>()
                .ToList();

But if you're just iterating over the elements and don't really need a List, you can leave off the call to GetList().

edited Sep 17 '12 at 14:40

answered Sep 17 '12 at 14:09

Justin Niessner

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`list` will be a `List` not `List`. – Rawling Sep 17 '12 at 14:10
@JustinNeissner - Justin having some problems with and without the ToList(). Cannot assign method group to implicitly typed local variable – dotnetnoob Sep 17 '12 at 14:26
@user1437135 - Are you sure you included all the appropriate parenthesis? – Justin Niessner Sep 17 '12 at 14:40
@JustinNiessner - definitely Justin, however I've rejigged things a little replcing the IBookmarkWrapper with BookmarkWrapper (a base class) and it worked. – dotnetnoob Sep 17 '12 at 15:02

Daniel A. White · Answer 2 · 2012-09-17T14:32:51.040

4

var list = deals.Select(d => new DealBookmarkWrapper(d))
                .Cast<IBookmarkWrapper>()
                .ToList();

edited Sep 17 '12 at 14:32

answered Sep 17 '12 at 14:09

Daniel A. White

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score 3 · Answer 3 · answered Sep 17 '12 at 14:10

3

How about

 var list = deals.ConvertAll(item=>new DealBookmarkWrapper(item));

answered Sep 17 '12 at 14:10

Justin Harvey

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score 1 · Answer 4 · answered Sep 17 '12 at 14:32

The question explicitly ask for 'adding a list into another list', so this one could be interesting too:

var list = new List<IBookmarkWrapper>();  //already existing
...  
deals.Aggregate(list, (s, c) => 
                      { 
                        s.Add(new DealBookmarkWrapper(c)); 
                        return s; 
                      });

Is it possible to recreate this statement without using a foreach?

4 Answers4

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