如何检测BindingList< T>中项目属性的更改？ [英] How can I detect changes to item properties in the BindingList<T>?

问题描述

我有一个自定义类Foo的属性A和B.我想显示在一个数据绑定控件。

I have a custom class Foo with properties A and B. I want to display it in a databinding control.

我创建了一个类 Foos：BindingList< Foo> 。

为了更新Foos类的一些内部属性，我需要通知属性更改我可以处理插入，删除等）列表中的项目。您将如何实现该功能？

In order to update some internal properties of the Foos class I need to be notified of property changes (I can handle insertions, removals etc.) on the items in the list. How would you implement that functionality ?

我应该从框架中的某个对象继承Foo吗？我想我可以创建事件通知我，如果改变，但是，它应该如何做？或者在框架中有一些模式，这会帮助我吗？

Should I inherit Foo from some object in the framework that supports that ? I think I could create events that notify me if changes, but is that the way it should be done ? Or is there some pattern in the framework, that would help me ?

推荐答案

Foo应该实现 INotifyPropertyChanged 和 INotifyPropertyChanging 接口。

Foo should implement the INotifyPropertyChanged and INotifyPropertyChanging interfaces.

public void Foo : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    private void NotifyPropertyChanged(String info)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(info));
        }
    }

    private int _someValue;
    public int SomeValue
    {
        get { return _someValue; }
        set { _someValue = value; NotifyPropertyChanged("SomeValue"); }
    }
}

BindingList应该自动挂钩到你的事件处理程序，现在你的GUI应该在你设置类调用PropertyChanged事件处理程序时更新。

The BindingList should hook onto your event handler automagically, and your GUI should now update whever you set your class invokes the PropertyChanged event handler.

此外，BindingList类发布了两个事件，当收集已添加或修改时通知您：

Additionally, the BindingList class exposted two events which notify you when the collection has been added to or modified:

public void DoSomething()
{
    BindingList<Foo> foos = getBindingList();
    foos.ListChanged += HandleFooChanged;
}

void HandleFooChanged(object sender, ListChangedEventArgs e)
{
    MessageBox.Show(e.ListChangedType.ToString());
}

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