WPF中监视DependencyProperty的变化

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WPF中监视DependencyProperty的变化

周银辉

尽管一个类会提供很多事件，但有时候还是显得不够，比如说前两天我就以为WPF的ListBox控件会有ItemsSourceChanged事件，但好像没有。这里有一个方法可以监视任何一个DependencyProperty的Changed，下面是demo：

public class People : DependencyObject
{
public static readonly DependencyProperty NameProperty =
DependencyProperty.Register("Name", typeof (string), typeof (People), new PropertyMetadata(default(string))); public string Name
{
get { return (string) GetValue(NameProperty); }
set { SetValue(NameProperty, value); }
}
}//.........
private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
{
var people = new People {Name = "zhang san"}; var descriptor = DependencyPropertyDescriptor.FromProperty(People.NameProperty, typeof (People));
descriptor.AddValueChanged(people, (o, args) => MessageBox.Show("name changed to " + people.Name)); people.Name = "Li si";
}