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c#.netienumerableilist

C# Convert IEnumerable to IList using .ToList()?

I am using an external library thats returns a IEnumerable. After I have recieved them I would like to add some models to the end. That only seems possible when using an IList or some other collection. So when i'm trying to convert the IEnumerable to a list using the .ToList() method it returns an IEnumerable. That's not the what I expected? Am I using .ToList() correct? Or what else would solve my problem?

This is my code i have so far:

IList<Models.Browser.Language> languages = GetLanguages(dateDrom, dateTo).ToList();
IList<Models.Browser.Language> primaryItems = languages.Take(10);

This last line produces an error saying: Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<Bogus.Models.Browser.Language>' to 'System.Collections.Generic.IList<Bogus.Models.Browser.Language>'. An explicit conversion exists (are you missing a cast?)

Thanks in advance!

Solution

  • The value of languages is a reference to a List<>, but then you're calling Take(10) on that, which doesn't return a list.

    Just move your ToList() call:

    IEnumerable<Models.Browser.Language> languages = GetLanguages(dateDrom, dateTo);
IList<Models.Browser.Language> primaryItems = languages.Take(10).ToList();

    Or just do it in one call:

    var primaryItems = GetLanguages(dateDrom, dateTo).Take(10).ToList();

    Also, this isn't quite correct:

    After I have recieved them I would like to add some models to the end.

    An alternative is to use Concat. For example:

    var items = GetLanguages(dateDrom, dateTo).Take(10).Concat(fixedItems);