当您没有类的源代码时，是否可以对对象进行 .NET 二进制序列化? [英] Is it possible to do .NET binary serialization of an object when you don't have the source code of the class?

问题描述

我正在使用 BinaryFormatter 对 C# 中的某些对象进行二进制序列化.但是，某些对象包含我通过 DLL 访问的类并且没有源代码，所以我不能用 Serializable 属性标记它们.有没有一种直接的方法来序列化它们?我有一个解决方法，它涉及获取类 NoSource 并创建一个新类 SerializableNoSource，其中构造函数获取一个 NoSource 对象并提取我的所有信息需要它，但它很hacky.有没有更好的选择?

I am using BinaryFormatter to do binary serialization of some objects in C#. However, some of the objects contain classes that I access via a DLL and do not have the source code for, so I can't mark them with the Serializable attribute. Is there a straightforward way to serialize them anyway? I have a workaround which involves taking class NoSource and making a new class SerializableNoSource for which the constructor takes a NoSource object and extracts all the information I need from it, but it's hacky. Are there any better alternatives?

推荐答案

您可以创建一个序列化代理.

想象一下，我们在引用程序集中定义了一个我们无法控制的类，如下所示:

Imagine that we have a class defined in a referenced assembly that we have no control over that looks like this:

public class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
    public DriversLicense License;
}


// An instance of this type will be part of the object graph and will need to be 
// serialized also.
public class DriversLicense
{
    public string Number { get; set; }
}

为了序列化这个对象，你需要为对象图中的每个类型定义一个序列化代理.

In order to serialize this object you will need to define a serialization surrogate for each type in the object graph.

要创建序列化代理，您只需创建一个实现 ISerializationSurrogate 接口:

To create a serialization surrogate you simply need to create a type that implements the ISerializationSurrogate interface:

public class PersonSurrogate : ISerializationSurrogate
{
    /// <summary>
    /// Manually add objects to the <see cref="SerializationInfo"/> store.
    /// </summary>
    public void GetObjectData(object obj, SerializationInfo info, StreamingContext context)
    {
        Person person = (Person) obj;
        info.AddValue("Name", person.Name);
        info.AddValue("Age", person.Age);
        info.AddValue("License", person.License);
    }

    /// <summary>
    /// Retrieves objects from the <see cref="SerializationInfo"/> store.
    /// </summary>
    /// <returns></returns>
    public object SetObjectData(object obj, SerializationInfo info, StreamingContext context, ISurrogateSelector selector)
    {
        Person person = (Person)obj;
        person.Name = info.GetString("Name");
        person.Age = info.GetInt32("Age");
        person.License = (DriversLicense) info.GetValue("License", typeof(DriversLicense));
        return person;
    }
}

public class DriversLicenseSurrogate : ISerializationSurrogate
{
    /// <summary>
    /// Manually add objects to the <see cref="SerializationInfo"/> store.
    /// </summary>
    public void GetObjectData(object obj, SerializationInfo info, StreamingContext context)
    {
        DriversLicense license = (DriversLicense)obj;
        info.AddValue("Number", license.Number);
    }

    /// <summary>
    /// Retrieves objects from the <see cref="SerializationInfo"/> store.
    /// </summary>
    /// <returns></returns>
    public object SetObjectData(object obj, SerializationInfo info, StreamingContext context, ISurrogateSelector selector)
    {
        DriversLicense license = (DriversLicense)obj;
        license.Number = info.GetString("Number");
        return license;
    }
}

然后，您需要通过定义和初始化 SurrogateSelector 并将其分配给您的 IFormatter 来让您的 IFormatter 了解代理项.

Then you need to let your IFormatter know about the surrogates by defining and initializing a SurrogateSelector and assigning it to your IFormatter.

private static void SerializePerson(Person person)
{
    if (person == null)
        throw new ArgumentNullException("person");

    using (var memoryStream = new MemoryStream())
    {
        //Configure our surrogate selectors.
        var surrogateSelector = new SurrogateSelector();
        surrogateSelector.AddSurrogate(typeof (Person), new StreamingContext(StreamingContextStates.All),
                                       new PersonSurrogate());
        surrogateSelector.AddSurrogate(typeof (DriversLicense), new StreamingContext(StreamingContextStates.All),
                                       new DriversLicenseSurrogate());

        //Serialize the object
        IFormatter formatter = new BinaryFormatter();
        formatter.SurrogateSelector = surrogateSelector;
        formatter.Serialize(memoryStream, person);

        //Return to the beginning of the stream
        memoryStream.Seek(0, SeekOrigin.Begin);

        //Deserialize the object
        Person deserializedPerson = (Person) formatter.Deserialize(memoryStream);
    }
}

使用序列化代理绝不简单，当您尝试序列化的类型具有 private &需要序列化的受保护字段.

Using a serialization surrogate is by no means straightforward, and can actually become quite verbose when the type you are trying to serialize has private & protected fields that need to be serialized.

但是由于您已经手动序列化了您需要的值，我认为这不是问题.使用代理是处理此类场景的更统一的方式，应该会让您感觉更舒服.

But as you are already manually serializing the values you need, I don't think that is an issue. The use of a surrogate is a more unifom way of handling a scenario like this and should make you feel more comfortable.

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