CollectionViewSource: LiveShaping properties do not work

Question

I'm using the CollectionViewSource with LiveShaping properties, especially Grouping activated. The problem is that changing the Grouping properties does not work immediately. It works however, when I refresh the view by manually calling Refresh on the View.

But the question is then, why do I have the LiveShaping properties on the CollectionViewSource if they do not work? Or I'm I doing something wrong?

Here is an example:

using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Windows.Data;

namespace ConsoleApplication6
{
    class Program
    {
        static void Main(string[] args)
        {
            ObservableCollection<Test> TestList = new ObservableCollection<Test>();

            for (int i = 0; i < 3; i++)
            {
                for (int j = 0; j < 3; j++)
                {
                    Test t = new Test()
                    {
                        Group = i.ToString(),
                        Name = (j + (i * 10)).ToString()
                    };

                    TestList.Add(t);
                }
            }

            CollectionViewSource aViewSource = new CollectionViewSource();
            aViewSource.Source = TestList;

            aViewSource.IsLiveGroupingRequested = true;
            aViewSource.GroupDescriptions.Add(new PropertyGroupDescription("Group"));
            aViewSource.LiveGroupingProperties.Add("Group");

            foreach (CollectionViewGroup o in aViewSource.View.Groups)
            {
                Console.WriteLine(o.Name);
                foreach (Test o2 in o.Items)Console.WriteLine("     " + o2.Name);
            }

            Console.WriteLine("----------------------------------------------");


            TestList[4].Group = "4";

            //aViewSource.View.Refresh(); When using this line it works.

            foreach (CollectionViewGroup o in aViewSource.View.Groups)
            {
                Console.WriteLine(o.Name);
                foreach (Test o2 in o.Items) Console.WriteLine("     " + o2.Name);
            }

            Console.WriteLine("----------------------------------------------");


            foreach (Test test in TestList)
            {
                Console.WriteLine("{0}: {1}", test.Group, test.Name);
            }


            Console.WriteLine("----------------------------------------------");
            Console.ReadKey();
        }
    }

    public class Test : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        private string myName;
        private string myGroup;

        public string Name
        {
            get
            {
                return myName;
            }

            set
            {
                myName = value;
                OnPropertyChanged();
            }
        }

        public string Group
        {
            get
            {
                return myGroup;
            }

            set
            {
                myGroup = value;
                OnPropertyChanged();
            }
        }


        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName_in = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName_in));
        }

        public override string ToString()
        {
            return $"{Group}: {Name}";
        }
    }
}

score 0 · Answer 1 · edited May 23 '17 at 12:25

0

A CollectionViewSource with live grouping enabled doesn't work in the context of a console application where there is no dispatcher available for the same reasons as being mentioned in the answers to your other question:

CollectionView without a dispatcher

edited May 23 '17 at 12:25

Community

1
1

answered Apr 11 '17 at 13:21

mm8

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Understood. But when using the same code in a WPF window the same code also does only work if I explicitly call the View.Refresh() method or if connect iot as an ItemsSource to a e.g. ListBox. – msedi Apr 12 '17 at 07:56
Please provide a WPF example of your issue then. – mm8 Apr 12 '17 at 08:44

CollectionViewSource: LiveShaping properties do not work

1 Answers1