data-binding - UWP - 将元素绑定(bind)到主窗口大小并随着窗口大小的变化更新值

Question

我想将窗口的当前大小绑定(bind)到文本 block 。在当前的实现中，主窗口的大小是在运行时设置的，但是如果我在应用程序启动后调整窗口大小，新的大小不会在文本 block 中更新。

<Grid x:Name="grid" Background="#FFE8E8E8">
   <TextBox x:Name="textBoxSample" Width="300" Height="200" Text="{Binding ActualWidth, ElementName=grid}"></TextBox>
</Grid>

Answer 1

您不应绑定(bind)到 ActualWidth。 FrameworkElement.ActualWidth的备注文档说:

Although it has an ActualWidthProperty backing field, ActualWidth does not raise property change notifications and it should be thought of as a regular CLR property and not a dependency property.

For purposes of ElementName binding, ActualWidth does not post updates when it changes (due to its asynchronous and run-time calculated nature). Do not attempt to use ActualWidth as a binding source for an ElementName binding. If you have a scenario that requires updates based on ActualWidth, use a SizeChanged handler.

您将需要一些其他方法来确定窗口的大小，例如通过订阅 SizeChanged 事件。