Question

我有Base class：

public abstract class WiresharkFile
{
    protected string _fileName;
    protected int _packets;
    protected int _packetsSent;
    protected string _duration;

    public int Packets
    {
        get { return _packets; }
        set { _packets = value; }
    }

    public int PacketsSent
    {
        get { return _packetsSent; }
        set { _packetsSent = value; }
    }
}

这个子类：

public class Libpcap : WiresharkFile, IDisposable, IEnumerable<WiresharkFilePacket>
{
    ....
}

创建我的对象：

WiresharkFile wiresahrkFile = new Libpcap(file);

我的收藏：

public ObservableCollection<WiresharkFile> wiresharkFiles { get; set; }

发送数据包：

wiresahrkFile.Sendpackets();

此时我的所有wiresahrkFile（Libpcap类型）属性都在发生变化，所以我想知道我需要在哪里定义INotifyPropertyChanged。

Answer 1

如果你的xaml绑定到WiresharkFile的属性，那么WiresharkFile必须实现INotifyPropertyChanged，否则会导致内存泄漏（Top 3 Memory Leak Inducing Pitfalls of WPF Programming）。如果仅在Libpcap类上定义绑定，则Libpcap必须实现INotifyPropertyChanged接口。在我的项目中，我创建了一个INotifyPropertyChanged接口的基本实现，然后每个基本模型和基本视图模型都继承自该实现。这里有一些基本代码： 1.基础实施：

public class BaseObservableObject : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        var handler = PropertyChanged;
        if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
    }

    protected virtual void OnPropertyChanged<T>(Expression<Func<T>> raiser)
    {
        var propName = ((MemberExpression)raiser.Body).Member.Name;
        OnPropertyChanged(propName);
    }

    protected bool Set<T>(ref T field, T value, [CallerMemberName] string name = null)
    {
        if (!EqualityComparer<T>.Default.Equals(field, value))
        {
            field = value;
            OnPropertyChanged(name);
            return true;
        }
        return false;
    }
}

2。你的模特（在我看来）：

public abstract class WiresharkFile:BaseObservableObject
{
    private string _fileName;
    private int _packets;
    private int _packetsSent;
    private string _duration;

    public int Packets
    {
        get { return _packets; }
        set
        {
            _packets = value;
            OnPropertyChanged();
        }
    }

    public int PacketsSent
    {
        get { return _packetsSent; }
        set
        {
            _packetsSent = value;
            OnPropertyChanged();
        }
    }
}

的问候，

Answer 2

与IIan的答案相同，但对于C＃8和.Net Framework 4.8。

1。基本模型

position="sticky"

2。您的模型

public class ObservableObject : INotifyPropertyChanged
{
        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

        protected virtual void OnPropertyChanged<T>(Expression<Func<T>> raiser)
        {
            string propName = ((MemberExpression)raiser?.Body).Member.Name;
            OnPropertyChanged(propName);
        }

        protected bool Set<T>(ref T field, T value, [CallerMemberName] string name = null)
        {
            if (!EqualityComparer<T>.Default.Equals(field, value))
            {
                field = value;
                OnPropertyChanged(name);
                return true;
            }
            return false;
        }
}

3。如何使用？

public class Current : ObservableObject
{
        private string _status;

        public Current()
        {
            Status = "Not Connected";
        }

        public string Status
        {
            get { return _status; }
            set
            {
                _status = value;
                OnPropertyChanged(); // call this to update
            }
        }
}

我需要在Base和子类的情况下定义INotifyPropertyChanged

2 个答案: