WPF LINQ and the ObservableCollection

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In my WPF application I'd like to use LINQ as much as possible (especially to avoid foreach). But WPF works a lot with the ObservableCollection, and I can't use LINQ with these kind of collection. What can I do?

What makes you think you can't use LINQ with ObservableCollection<T>? It implements Collection<T> so it should be fine.

For example:

using System;
using System.Collections.ObjectModel;
using System.Linq;

class Test
{
    static void Main()
    {
        var collection = new ObservableCollection<int>()
        {
            1, 2, 3, 6, 8, 2, 4, 5, 3
        };

        var query = collection.Where(x => x % 2 == 0);
        foreach (int x in query)
        {
            Console.WriteLine(x);
        }
    }
}

WPF LINQ and the ObservableCollection, What makes you think you can't use LINQ with ObservableCollection<T> ? It implements Collection<T> so it should be fine. For example: Purpose. ObservableCollection<T> is not strictly a WPF class, but its intended purpose seems to be for use in WPF. It's the standard implementation of INotifyCollectionChanged, an interface which is special-cased by some WPF widgets to provide efficient UI updates and to maintain state effectively.

Just for anybody else who may come across this issue with trying to filter an ObservableCollection but find that they can't.

Jon is absolutely correct in that there is no reason why you can't do this but the key thing for a newbie or for someone who has been developing with WPF for a while, is that you need to include the "using System.Linq;" namespace. As you soon as you do this, you can do a ".where" query on your object.

Linq for ObservableCollection, ObservableCollection<T> is not strictly a WPF class, but its intended with ObservableCollection , replace Linq Select in the view-model (to� Linq is declarative. The two cannot be used together without extra help. Imperative code explicitly acts upon something. When using an ObservableCollection, you explicitly call Add, Remove, and other methods to change the collection.

The OP asked especially for the LINQ ".ForEach()" Method, which cannot be used on ObservableCollection< T >, since it's implemented for List< T > only.

There is another SO-Topic, where I found my solution: https://stackoverflow.com/a/200584/2408978

Querying a Observable Collection ? - MSDN, yes, Linq is your friend: var customers = new ObservableCollection<Customer>( new[] { new Customer {Name = "Foo", Number = "No 1"}, new� Question: Tag: wpf,linq,entity-framework-6,observablecollection I'm new to wpf, Entity Framework 6 and LINQ. I'm having a data grid bounded to a CollectionViewSource, which is bounded to ObservableCollection.

You need my ObservableComputations library maybe. That is .NET API designed especially to work with LINQ like queries to ObservableCollection in WPF and other .NET UI frameworks that support binding to INotifyCollectionChanged and INotifyPropertyChanged objects (Xamarin, Blazor).

[Solved] Using LINQ on ObservableCollection with GroupBy , The error message tells you directly that the return value of the Property must be the expected Type of the Property. That indicates to me you� ObservableCollection<Foo> x = new ObservableCollection<Foo>(enumerable); That will do the required copying. There's no way of observing changes to the live query - although the idea of an ObservableQuery<T> is an interesting (though challenging) one.

Using ObservableCollection with Linq, It's not easy. Let's say you've got a composite object which contains an observable collection (because you want to bind it to a list box for� How to: Create and Bind to an ObservableCollection. 03/30/2017; 2 minutes to read +8; In this article. This example shows how to create and bind to a collection that derives from the ObservableCollection<T> class, which is a collection class that provides notifications when items get added or removed.

[SOLVED], to wpf, Entity Framework 6 and LINQ. I'm having a data grid bounded to a CollectionViewSource, which is bounded to ObservableCollection. Hi agung; What the error message is saying is that the Linq query is returning a IQueryable of TabelSignature and the ObservableCollection you created holds objects of FileSignature, they need to be of the same type. Now what you can do is make the ObservableCollection holds objects of type TabelSignature and change your code as follows

Common mistakes while using ObservableCollection, ObservableCollection is one of the most useful classes in WPF and When using linq, you declare what a collection will look like, how it will be� Hi. I would like to check if an ObservableCollection contains an object using its properties. At the moment, I'm just using checking using the .name property :

Comments
  • Thank you. Sorry. I remember there were problems with some queries, but now I have tried and everything works.
  • The resulting query is an IEnumerable. Is there a clean way of going back into an ObservableCollection<int> ?
  • @ToaoG: That takes a copy of the data - it won't change when the original observable collection changes, which is what I'd expected tofutim to require. I could have misunderstood though.
  • @ToaoG: If you're going to filter it so that you don't actually observe any changes in the original data, what good is it doing you to use ObservableCollection at all? What changes will you observe?
  • @ToaoG: You didn't answer my question: why bother using an ObservableCollection at all, if you're not going to be able to observe any changes? (Because it's a copy of the data.)
  • Thanks for the additional answer! That was my issue :)
  • The resulting ObservableCollection will not update if the query result update as a consequence of the underlying source being updated.