INotifyCollectionChanged [英] INotifyCollectionChanged

问题描述

我正在将GridView绑定到CollectionViewSource，因此：

        < GridView中的ItemsSource = QUOT; {绑定源= {StaticResource的ItemsViewSource}}"

在CVS被这样定义：

&NBSP;&NBSP; &NBSP;&NBSP;&NBSP;&NBSP;&NBSP; < CollectionViewSource X：名称= QUOT; ItemsViewSource"

&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;源= QUOT; {结合基团}"

&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; IsSourceGrouped = QUOT;真"

&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; ItemsPath = QUOT;物品" />

组是从的ObservableCollection衍生所以实现INotifyCollectionChanged&NBSP;

这个问题似乎是，即使物品（ItemsPath上文）实现INotifyCollectionChanged，当我从Items添加，更改或删除项目时，网格视图不会更新。我必须强制重新绑定CVS。

解决方案

也许这会有所帮助：

- 生成一个新的网格应用程序

- 在GroupedItemPage上添加一个Button，并在下面添加一个代码隐藏代码段。
- 运行并单击按钮：组1已更新

<预类= "prettyprint">私人无效Button_Click_1（对象发件人，RoutedEventArgs E）
{
变种GRP = SampleDataSource.GetGroup（QUOT;组-1。"）;
grp.Items.Insert（0，new SampleDataItem（" Group-1-Item-1"，
" Item Title：1"，
" Item Subtitle：a new Item" ;，
"Assets / LightGray.png"，
"A new Item"，
"A new Item"，
grp））;
}

通过在调试步骤模式中执行上述"插入"，您可能会发现"TopItems"与"TopItems"之间的区别。组更新在Grid App模板和您的实现中处理。

I'm binding a GridView to a CollectionViewSource, thus:

        <GridView ItemsSource="{Binding Source={StaticResource ItemsViewSource}}"

The CVS is defined thus:

        <CollectionViewSource x:Name="ItemsViewSource"
                              Source="{Binding Groups}"
                              IsSourceGrouped="true"
                              ItemsPath="Items" />

Groups is derived from ObservableCollection so implements INotifyCollectionChanged. 

The problem seems to be that even though the Items (ItemsPath above) implements INotifyCollectionChanged, when i add, change or remove items from Items, the grid view doesnt update. I have to force a re-bind of the CVS.

解决方案

Maybe this will help:

- generate a new Grid App
- add a Button on the GroupedItemPage and the code-behind snippet below
- run and click Button: Group 1 is updated

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            var grp = SampleDataSource.GetGroup("Group-1");
            grp.Items.Insert(0, new SampleDataItem("Group-1-Item-1",
                                             "Item Title: 1",
                                             "Item Subtitle: A new Item",
                                             "Assets/LightGray.png",
                                             "A new Item",
                                             "A new Item",
                                             grp));
        }

By following the above 'Insert' in debug step mode, you'll probably find the difference between how the "TopItems" group update is handled in the Grid App template and your implementation.

这篇关于INotifyCollectionChanged的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！