Linq cast to Dictionary

Question

I have a Dictionary

Dictionary<string, List<MyClass>> MyDictionary = new Dictionary<string,List<MyClass>>();

I am using Linq to obtain a List (from value) via the key

List<MyClass> CurrentList = null; CurrentList = MyDictionary.Where(d => d.Key.Contains(strKey)).Select(x => x.Value).Cast<Dictionary<string, List<MyClass>>>();

The error I am getting is I can not convert the dictionary to my list.

Have I missed anything?

Thanks.

Why do you cast to a Dictionary if your result must be a List? — Marius Bancila
– Marius Bancila, Commented Aug 22, 2014 at 7:52

Tim.Tang · Accepted Answer · 2014-08-22 07:54:31Z

Try this:

As x.Value is List<MyClass>, so you need use SelectMany:

 List<MyClass> CurrentList = null; CurrentList = MyDictionary.Where(d => d.Key.Contains(strKey)) .SelectMany(x => x.Value).ToList();

user3559224 · Accepted Answer · 2014-08-22 07:53:13Z

Try it

List<MyClass> CurrentList = null; CurrentList = MyDictionary.Where(d => d.Key.Contains(strKey)).ToList() .Where(x => x.Value);

Jason Evans · Accepted Answer · 2014-08-22 07:55:59Z

0

The issue is here:

.Select(x => x.Value)

x.Value is of type List<MyClass>, so you cannot cast it as a dictionary. So to fix your code, just use:

CurrentList = MyDictionary.Where(d => d.Key.Contains(strKey)).Select(x => x.Value).FirstOrDefault();

edited Aug 22, 2014 at 7:55

answered Aug 22, 2014 at 7:50

Jason Evans

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2 Comments

nullVoid Over a year ago

Thanks. Cannot implicitly convert error is now coming up.

Jason Evans Over a year ago

I've changed my code, as I forgot to include FirstOrDefault() to retrieve the List (assuming you want just one item returned, if you want more than one, then the other answers given for this question, using SelectMany, should work for you).

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