Question

我有一个非常基本的类，具有1个属性，如下所示：

public class NodeItem
{
    private object _Value;

    public object Value
    {
        get { return _Value; }
        set { _Value = value; }
    }
}

只要Value属性的值更改，如何定义事件？

Answer 1

这是一个简单的例子

public event PropertyChangedEventHandler PropertyChanged;

private object _Value;
public object Value
{
    get { return _value; }
    set
    {
        _value = value;
        // Call OnPropertyChanged whenever the property is updated
        OnPropertyChanged(value);
    }
}


protected void OnPropertyChanged(object val)
{
    PropertyChangedEventHandler handler = PropertyChanged;
    if (handler != null)
    {
        handler(this, new PropertyChangedEventArgs(val));
    }
}

Reference

用于订阅事件

void MyEventSubscription(object sender, CustomEventArgs a)  
{  
    // Do something useful here.  
}  

myClassInstance.PropertyChanged += MyEventSubscription;

属性值更改后，以C＃Windows窗体定义事件

1 个答案: