有什么方法可以获取变量何时更改吗?如果是这样,我怎样才能实现这一目标?
“官方”的方法是INotifyPropertyChanged
。例如。当控件绑定到的数据对象更新时,UI(Windows 窗体、WPF)使用它来自动刷新控件。
public class MyClass : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
...
}
然后你可以实现这样的属性
private string _name;
public string Name
{
get { return _name; }
set {
if (value != _name) {
_name = value;
OnPropertyChanged(nameof(Name));
}
}
}
你可以这样使用它:
var myObj = new MyClass();
myObj.PropertyChanged += MyObj_PropertyChanged;
myObj.Name = "new name";
// Clean up (e.g. in a `Dispose()` method)
myObj.PropertyChanged -= MyObj_PropertyChanged;
假设这个事件处理程序:
// Will be called whenever a property of `MyClass` is updated.
private void MyObj_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
// Example
if (e.PropertyName == nameof(MyClass.Name)) {
var myObj = (MyClass)sender;
//TODO: do something.
}
}
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