C# - convert anonymous type to observablecollection

Question

I have a LINQ statement that returns an anonymous type. I need to get this type to be an ObservableCollection in my Silverlight application. However, the closest I can get it to a

List myObjects;

Can someone tell me how to do this?

ObservableCollection<MyTasks> visibleTasks = e.Result;
var filteredResults = from visibleTask in visibleTasks
                      select visibleTask;

filteredResults = filteredResults.Where(p => p.DueDate == DateTime.Today);
visibleTasks = filteredResults.ToList();  // This throws a compile time error

How can I go from a anonymous type to an observable collection?

Thank you

score 6 · Accepted Answer · edited Jul 15 '14 at 15:49

As Ekin suggests, you can write a generic method that turns any IEnumerable<T> into an ObservableCollection<T>. This has one significant advantage over creating a new instance of ObservableCollection using constructor - the C# compiler is able to infer the generic type parameter automatically when calling a method, so you don't need to write the type of the elements. This allows you to create a collection of anonymous types, which wouldn't be otherwise possible (e.g. when using a constructor).

One improvement over Ekin's version is to write the method as an extension method. Following the usual naming pattern (such as ToList or ToArray), we can call it ToObservableCollection:

static ObservableCollection<T> ToObservableCollection<T> 
  (this IEnumerable<T> en) { 
    return new ObservableCollection<T>(en); 
}

Now you can create an observable collection containing anonymous types returned from a LINQ query like this:

var oc = 
  (from t in visibleTasks   
   where t.IsSomething == true
   select new { Name = t.TaskName, Whatever = t.Foo }
  ).ToObservableCollection();

Is there a way to do it without using generics? I mean, with inline code and without creating a real type. Something like ObservableCollection ? — v1n1akabozo, Jun 12 '16 at 16:20

score 2 · Answer 2 · answered Feb 26 '10 at 19:23

Something like this would do the job using type inference features:

private static ObservableCollection<T> CreateObservable<T>(IEnumerable<T> enumerable)
{
    return new ObservableCollection<T>(enumerable);
}

static void Main(string[] args)
{

    var oc = CreateObservable(args.Where(s => s.Length == 5));
}

score 1 · Answer 3 · answered Feb 26 '10 at 19:22

1

You should just be able to do this:

visibleTasks = new ObservableCollection<MyTasks>(filteredResults);

answered Feb 26 '10 at 19:22

BFree

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score 0 · Answer 4 · edited May 23 '12 at 17:28

0

Try:

var filteredResults = from visibleTask in visibleTasks
                      where(p => p.DueDate == DateTime.Today)
                      select visibleTask).ToList();

(filteredResults will contain your desired list)

edited May 23 '12 at 17:28

Kirk Woll

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answered May 23 '12 at 17:25

ramnz

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score 0 · Answer 5 · answered Feb 26 '10 at 19:19

0

Are you sure that your object is an ObservableCollection indeed? If yes, you can just cast: visibleTasks = (ObservableCollection)filteredResults;

answered Feb 26 '10 at 19:19

Vlad

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C# - convert anonymous type to observablecollection

5 Answers5