My CollectionViewSource is not picking up changes

Question

I have a ListView which I'm binding to a CollectionViewSource in code behind with:

collectionView = CollectionViewSource.GetDefaultView(TableView.ItemsSource);
collectionView.SortDescriptions.Clear();
collectionView.SortDescriptions.Add(new SortDescription(propertyName, direction));

The TableView is the ListView, the propertyName is the name of the column I want sorted, and direction is either ascending or descending.

The XAML has the following for ItemSource:

ItemsSource="{Binding Rows}"

The code behind has the following for the Rows:

List<TableRow> rows;

public List<TableRow> Rows
{
    get { return rows; }
    set 
    {
        rows = value;
        UpdateProperty("Rows");
    }
}

the update is as follows:

public void Update()
{
     ...generate a list of rows...

     Rows = ...rows...
}

The problem occurs when the Update is called, the list view does update, but loses the sorting set previously on the CollectionViewSource.

paparazzo · Accepted Answer · 2012-04-11T16:23:13.367

4

If you are "newing" rows then any setting on the prior rows is gone. If you clear (not new) the rows then I think they will hold the setting.

And you don't even want Rows = rows in update. After assign rows then.

NotifyPropertyChange("Rows");

So the UI know to update

If you are going to new then reassign

collectionView = CollectionViewSource.GetDefaultView(TableView.ItemsSource);
collectionView.SortDescriptions.Clear();
collectionView.SortDescriptions.Add(new SortDescription(propertyName, direction));

Maybe

private List<TableRow> rows = new List<TableRow>();

and have that the only place you new it

edited Apr 11 '12 at 16:23

answered Apr 11 '12 at 16:12

paparazzo

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Unfortunately, using Rows = rows is a requirement for what I'm working on. – imekon Apr 12 '12 at 08:06
1

@imekon And just why is Rows = rows a requirement? – paparazzo Apr 12 '12 at 13:20

imekon · Answer 2 · 2012-04-13T10:32:54.707

2

The answer is to reapply the sort descriptions after the update, as in:

collectionView = CollectionViewSource.GetDefaultView(TableView.ItemsSource);  
collectionView.SortDescriptions.Clear();
collectionView.SortDescriptions.Add(new SortDescription(propertyName, direction));

Then the sorting isn't lost. Refresh on the collection view doesn't help.

edited Apr 13 '12 at 10:32

answered Apr 12 '12 at 10:43

imekon

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That is exactly what I said in my answer 23 hours ago. If you are going to new then reassign ... – paparazzo Apr 12 '12 at 15:54
That's true, I was hoping Refresh or something simpler would do it. – imekon Apr 13 '12 at 10:33

Naser Asadi · Answer 3 · 2013-01-17T23:57:26.490

2

If an item property value involved in one of the grouping, sorting and filtering operations is updated, then the sorting/grouping/filtering will not be done again.

WPF 4.5 introduce a feature called live shaping which shapes the collection view in live.

See this article for more info.

edited Jan 17 '13 at 23:57

answered Jan 14 '13 at 11:23

Naser Asadi

1,153
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score 0 · Answer 4 · answered Apr 12 '12 at 09:08

Did you try to do CollectionView.Refresh() after your update?

If this does not help then I think your problem occurs because you change the source of your CollectionView by assigning new value to your Rows list.

I don't know if it is possible to your code but don't assign new list just clear your previous one and insert new rows there.

if (Rows != null)
   Rows.Clear();
   Rows.TrimExcess();
else
   Rows = new List<TableRow>();

My CollectionViewSource is not picking up changes

4 Answers4

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