如何刷新Metro应用程序中的UI? [英] How to refresh the UI in a metro app?

问题描述

我正在XAML页面中使用以下代码:

I'm using this code in a XAML page:

<TextBox ItemsSource="{Binding Posters, Converter={StaticResource collectionToFirstElementConverter}, Mode=TwoWay}" />

Posters是一个ObsevableCollection，我正在使用一个转换器，在其中使用该集合并获取它的第一个元素.

Posters is an ObsevableCollection and I'm using a converter where takes the collection and gets the first element of it.

当我使用异步过程时，文本框在其中接收对象，因此该对象没有任何元素(Count = 0)，并调用转换器.

As I'm using async procedures, where the textbox receives the object, this one has no elements (Count=0), and calls the converter.

每次属性添加新元素时，我都尝试更新文本框，但不调用转换器.

I'm trying to update the textbox everytime the property add new elements, but not calls the converter.

我记得在Silverlight或WPF中，存在SourceTrigger或UpdatePropertyChanged，但是在WinRT中，我看不到此模式.

I remember that in Silverlight or WPF, exists SourceTrigger or UpdatePropertyChanged, but in WinRT I can't see this mode.

推荐答案

最简单的方法是修改包含Posters属性的视图模型.我可以看到两种解决方法(都假设您的视图模型实现了INotifyPropertyChanged):

The easiest way to achieve that would be to modify your view model containing the Posters property accordingly. I can see two ways to go about it (both asuming that your view model implements INotifyPropertyChanged):

• 向Posters.CollectionChanged添加事件处理程序，并在其中将INotifyPropertyChanged.PropertyChanged提升为Posters.
• 添加另一个属性FirstPoster，返回Posters中第一个元素的值.在视图模型中，将事件处理程序添加到Posters.CollectionChanged，并在其中将INotifyPropertyChanged.PropertyChanged引发为FirstPoster.这样，您甚至都不需要转换器.

• Add an event handler to Posters.CollectionChanged and inside it raise INotifyPropertyChanged.PropertyChanged for Posters.
• Add another property FirstPoster returning the value of the first element in Posters. In the view model add an event handler to Posters.CollectionChanged and inside it raise INotifyPropertyChanged.PropertyChanged for FirstPoster. This way you don't even need the converter.

我个人更喜欢第二种方法.

I personally like the second approach better.

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