绑定不适用于导航属性

发布于 2024-08-15 21:10:31 字数 463 浏览 2 评论 0原文

我正在将 WPF 与实体框架绑定。

Window.DataContext 属性设置为 Quote。此 Quote 有一个属性 Job，我必须触发它应该从服务器加载的 Quote.JobReference.Load 。

<ContentControl Content="{Binding Job}" 
    ContentTemplate="{StaticResource JobTemplateSummary}"/>

正如您在上面看到的，我试图将 ContentControl 绑定到窗口的 DataContext，它是一个 StaticResource Quote班级。

我正在 Window.Load 事件处理程序中调用 Load。我应该打电话到其他地方吗？

原文

I am binding WPF with Entity-Framework.

The Window.DataContext property is set to a Quote.
This Quote has a property Job, that I have to trigger Quote.JobReference.Load it should load from the server.

<ContentControl Content="{Binding Job}" 
    ContentTemplate="{StaticResource JobTemplateSummary}"/>

As you can see above, I am trying to bind a ContentControl to the Window's DataContext which is a StaticResource Quote class.

I am calling the Load in the Window.Load even handler.
Should I've called somewhere else?

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

等待圉鍢 2024-08-22 21:10:31

问题是导航属性默认情况下不会调用 PropertyChanged 事件，因此当窗口绑定时（在 Page_Load 处理程序之前），JobReference 仍未加载，我们必须调用 Quote。当作业属性更改时显式显示 OnPropertyChanged("Job")，以便 WPF UI 知道刷新控件绑定。

我将以下内容添加到 Quote 类中，这解决了问题：

Public Sub New()
    AddHandler JobReference.AssociationChanged, _
        AddressOf Job_AssociationChanged
End Sub

Sub Job_AssociationChanged(sender As Object, e As CollectionChangeEventArgs)
    OnPropertyChanged("Job")
End Sub

The problem was that Navigation Properties don't call PropertyChanged event by default so when the window is bound (which is before Page_Load handler) the JobReference was still not Loaded, we have to call Quote.OnPropertyChanged("Job") explicitly when the job property changes, so the WPF UI knows to refresh the control binding.

I added the following to the Quote class, and this solved the problem:

Public Sub New()
    AddHandler JobReference.AssociationChanged, _
        AddressOf Job_AssociationChanged
End Sub

Sub Job_AssociationChanged(sender As Object, e As CollectionChangeEventArgs)
    OnPropertyChanged("Job")
End Sub

回复收藏 0 原文

~没有更多了~