Question

我想构建一个对象列表。列表中的对象将引发一个事件，该对象应从列表中删除。我该如何建立这种机制？那种机制逻辑吗？

public class object()
{
   public event EventHandler listEmpty;
   List<string> name;
   ...

   public void Delete(string n)
   {
      name.Remove(n);
       ...

      if(name.isEmpty())
         //raise an event hier..
   }
}

public class MyClass
{
   public List<object> ObjList = new List<object>();

   public Remove(string x)
   {
      ObjList[5].Delete(x);
   }

    private void OnListIsEmpty(object sender, EventArgs e)
    { 
       ObjList.RemoveAt(5);
    }

    public MyClass()
    {
       // how to subscribe this event??
    }
}

Answer 1

我认为ObservableCollection和INotifyPropertyChanged符合您的要求。请参阅以下示例。

public class Model : INotifyPropertyChanged
{
    public Model(string val)
    {
        Value = val;
    }

    string Value { get; set; }

    public event PropertyChangedEventHandler PropertyChanged;
}

static void Main(string[] args)
{
    ObservableCollection<Model> collection = new ObservableCollection<Model>();
    collection.Add(new Model("item1"));
    collection.Add(new Model("item2"));
    collection.Add(new Model("item3"));
    collection.CollectionChanged += (sender, e) =>
    {
        if (e.Action == NotifyCollectionChangedAction.Remove)
        {
            var removedItems = e.OldItems; // put a breakpoint here to observe
        }
    };

    collection.RemoveAt(1);

    Console.ReadLine();
}

如何订阅从对象列表中的对象引发的事件

1 个答案: