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如何从[Serializable]INotifyPropertyChanged实现器中排除不可序列化的观察者?

inotifypropertychanged remoting serialization c#

12

skolima · 技术社区 · 17 年前

我有将近一百个实体类,看起来像这样:

[Serializable]
public class SampleEntity : INotifyPropertyChanged
{
    private string name;
    public string Name
    {
        get { return this.name; }
        set { this.name = value; FirePropertyChanged("Name"); }
    }

    [field:NonSerialized]
    public event PropertyChangedEventHandler PropertyChanged;

    private void FirePropertyChanged(string propertyName)
    {
        if (this.PropertyChanged != null)
            this.PropertyChanged(this,
                new PropertyChangedEventArgs(propertyName));
    }
}

注意 [field:NonSerialized] PropertyChanged . 这是必要的,因为一些观察者(在我的例子中,显示实体的网格用于编辑)可能不可序列化,并且实体必须是可序列化的,因为它是通过远程处理由在分离机器上运行的应用程序提供的。

此解决方案适用于一般情况。然而,有些观察员可能是 [Serializable] ,并须予以保存。我该怎么处理?

满的 ISerializable -自定义序列化需要编写大量代码,我不希望这样做
[OnSerializing] 和 [OnDeserializing] 财产变更 手动-但是那些助手方法只提供 SerializationContext ,AFAIK不存储序列化数据( SerializationInfo

1 回复 | 直到 17 年前

1

12

Tim Cooper 14 年前

Entity 实现的类 ISerializable , 所有子类还必须手动实现序列化 !

让第二个选项工作的诀窍是继续将事件标记为不可序列化,但要有第二个字段是

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            var entity = new Entity();
            entity.PropertyChanged += new SerializableHandler().PropertyChanged;
            entity.PropertyChanged += new NonSerializableHandler().PropertyChanged;

            Console.WriteLine("Before serialization:");
            entity.Name = "Someone";

            using (var memoryStream = new MemoryStream())
            {
                var binaryFormatter = new BinaryFormatter();
                binaryFormatter.Serialize(memoryStream, entity);
                memoryStream.Position = 0;
                entity = binaryFormatter.Deserialize(memoryStream) as Entity;
            }

            Console.WriteLine();
            Console.WriteLine("After serialization:");
            entity.Name = "Kent";

            Console.WriteLine();
            Console.WriteLine("Done - press any key");
            Console.ReadKey();
        }

        [Serializable]
        private class SerializableHandler
        {
            public void PropertyChanged(object sender, PropertyChangedEventArgs e)
            {
                Console.WriteLine("  Serializable handler called");
            }
        }

        private class NonSerializableHandler
        {
            public void PropertyChanged(object sender, PropertyChangedEventArgs e)
            {
                Console.WriteLine("  Non-serializable handler called");
            }
        }
    }

    [Serializable]
    public class Entity : INotifyPropertyChanged
    {
        private string _name;
        private readonly List<Delegate> _serializableDelegates;

        public Entity()
        {
            _serializableDelegates = new List<Delegate>();
        }

        public string Name
        {
            get { return _name; }
            set
            {
                if (_name != value)
                {
                    _name = value;
                    OnPropertyChanged("Name");
                }
            }
        }

        [field:NonSerialized]
        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged(PropertyChangedEventArgs e)
        {
            var handler = PropertyChanged;

            if (handler != null)
            {
                handler(this, e);
            }
        }

        protected void OnPropertyChanged(string propertyName)
        {
            OnPropertyChanged(new PropertyChangedEventArgs(propertyName));
        }

        [OnSerializing]
        public void OnSerializing(StreamingContext context)
        {
            _serializableDelegates.Clear();
            var handler = PropertyChanged;

            if (handler != null)
            {
                foreach (var invocation in handler.GetInvocationList())
                {
                    if (invocation.Target.GetType().IsSerializable)
                    {
                        _serializableDelegates.Add(invocation);
                    }
                }
            }
        }

        [OnDeserialized]
        public void OnDeserialized(StreamingContext context)
        {
            foreach (var invocation in _serializableDelegates)
            {
                PropertyChanged += (PropertyChangedEventHandler)invocation;
            }
        }
    }
}