INotifyPropertyChanged的目的是什么?我知道每当更改属性时都会触发此事件,但View/UI如何知道此事件被触发:
这是我的Customer类,它实现了INotifyPropertyChanged事件:
public class Customer : INotifyPropertyChanged
{
private string _firstName;
public string LastName { get; set; }
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string propertyName)
{
if(PropertyChanged != null)
PropertyChanged(this,new PropertyChangedEventArgs(propertyName));
}
public string FirstName
{
get { return _firstName; }
set
{
_firstName = value;
OnPropertyChanged("FirstName");
}
}
}
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但现在如何通知UI属性已更改.就像用户为第一个名称指定null或empty一样,如何在UI上显示MessageBox.