我已经实现了自定义DependencyProperty,并希望从XAML绑定它。但不知何故,当绑定源(MainWindow.Test)更新时,它并未更新。绑定源不是DP,但触发了PropertyChanged事件。但使用非自定义依赖属性时更新是有效的。
<TextBlock Text="{Binding Test}" />
无法工作:
<local:DpTest Text="{Binding Test}"/>
有什么想法吗?
这里是DP实现::
using System;
using System.Windows;
using System.Windows.Controls;
namespace WpfApplication3
{
public partial class DpTest : UserControl
{
public DpTest()
{
DataContext = this;
InitializeComponent();
}
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
public static readonly DependencyProperty TextProperty = DependencyProperty.Register("Text", typeof(string), typeof(DpTest), new PropertyMetadata(string.Empty, textChangedCallBack));
static void textChangedCallBack(DependencyObject property, DependencyPropertyChangedEventArgs args)
{
int x = 5;
}
}
}
这是它的使用方法:
<Window x:Class="WpfApplication3.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:local="clr-namespace:WpfApplication3" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:sys="clr-namespace:System;assembly=mscorlib" Title="MainWindow" Height="350" Width="525">
<StackPanel>
<TextBlock Text="{Binding Test}"></TextBlock>
<local:DpTest Text="{Binding Test}"></local:DpTest>
<Button Click="Button_Click">Update</Button>
</StackPanel></Window>
使用数据绑定源的代码后置:
using System;
using System.Collections.Generic;
using System.Windows;
using System.ComponentModel;
namespace WpfApplication3
{
public partial class MainWindow : Window, INotifyPropertyChanged
{
public MainWindow()
{
DataContext = this;
InitializeComponent();
}
string _test;
public string Test
{
get { return _test; }
set
{
_test = value;
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs("Test"));
}
}
}
private void Button_Click(object sender, RoutedEventArgs e)
{
Test = "Updatet Text";
}
public event PropertyChangedEventHandler PropertyChanged;
}
}