WPF DataBinding来控制属性 [英] WPF DataBinding to control properties
问题描述
我有一个问题,即我没有通过绑定接收更新。
我有一个标签,它通过DataContext绑定到TextBox属性的ExtentWidth。
我的绑定最初工作,并在标签中显示值0但是在此之后它不会更新。
ExtentWidth是一个只读属性,我不确定是否这会以任何方式影响绑定,但我有一个标签,当它被设置时绑定到文本,所以我知道它可以接收更新。 (按钮更新文字和标签更新)
下面是一些代码来证明我的问题。
I have an issue whereby I am not receiving updates through my bindings.
I have a label which is bound to the ExtentWidth of the TextBox property via the DataContext.
My binding initially works and displays the value of 0 in the label however it does not update after this.
ExtentWidth is a read only property, I'm not sure if this affects the binding in any way but I have a label the binds to the text when it is set so I know it can receive updates. (button updates text and label is updated)
below is some code to demonstrate my issue.
<Window x:Class="TestHarnesses.Views.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
<Grid>
<StackPanel>
<ContentPresenter x:Name="ContentPresenter" Content="{Binding}"></ContentPresenter>
<Label x:Name="lblExtentWidth"
Content="{Binding ExtentWidth, Mode=OneWay}"/>
<Label x:Name="lblText"
Content="{Binding Text, Mode=OneWay}"/>
<Button Content="Different Jibber Jabber" Click="ButtonBase_OnClick"/>
</StackPanel>
</Grid>
</Window>
using System.Windows;
using System.Windows.Controls;
namespace TestHarnesses.Views
{
/// <summary>
/// Interaction logic for Window1.xaml
/// </summary>
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
TextBox tb = new TextBox(){Text = "Jibber Jabber"};
this.TestTextBox = tb;
}
public TextBox TestTextBox
{
get { return (TextBox)GetValue(TestTextBoxProperty); }
set { SetValue(TestTextBoxProperty, value); }
}
// Using a DependencyProperty as the backing store for TestTextBox. This enables animation, styling, binding, etc...
public static readonly DependencyProperty TestTextBoxProperty =
DependencyProperty.Register("TestTextBox", typeof(TextBox), typeof(Window1), new PropertyMetadata(OnTestTextBoxProperty));
private static void OnTestTextBoxProperty(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((Window1) d).DataContext = (TextBox) e.NewValue;
}
private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
{
TestTextBox.Text = "Different Jibber Jabber";
}
}
}
推荐答案
TextBoxBase.ExtentWidth [ ^ ]不是 DependencyProperty [ ^ ]。您可以绑定它,但是当值发生变化时,没有任何方法可以通知绑定。
TextBoxBase.ExtentWidth[^] is not a DependencyProperty[^]. You can bind to it, but there isn't any way for the binding to be notified when the value changes.
这篇关于WPF DataBinding来控制属性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!