c# - 我的 CollectionViewSource 没有收到更改

Question

我有一个 ListView，我在后面的代码中绑定到 CollectionViewSource：

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

TableView就是ListView，propertyName就是我要排序的列名，方向是升序或者降序。

XAML 对 ItemSource 具有以下内容：

ItemsSource="{Binding Rows}"

后面的代码对行有以下内容：

List<TableRow> rows;

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

更新如下：

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

     Rows = ...rows...
}

调用 Update 时会出现问题，列表视图会更新，但会丢失之前在 CollectionViewSource 上设置的排序。

Answer 1

如果您正在“更新”行，那么之前行上的任何设置都将消失。如果您清除（不是新的）行，那么我认为它们将保留该设置。

而且您甚至不希望更新中的行 = 行。然后在分配行之后。

NotifyPropertyChange("Rows"); 

所以 UI 知道要更新

如果你要去新的然后重新分配

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

Answer 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.

Answer 3

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.

Answer 4

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>();