ISerializable的和向后兼容性 [英] ISerializable and backward compatibility

问题描述

您好 我要工作的一个旧的应用程序所使用BinaryFormatter的应用程序数据序列化到FILESTREAM（名为data.oldformat的文件说） 没有任何optimizazion主类已被打上属性

hello I have to work an an old application that used binaryFormatter to serialize application data into filestream (say in a file named "data.oldformat") without any optimizazion the main class has been marked with attribute

<serializable()>public MainClass
....... 
end class

和序列化code

dim b as new binaryformatter
b.serialize(mystream,mymainclass)

在一个试图优化序列化/反序列化过程中，我只是做了类实现ISerializable接口，并写了一些优化的序列化程序

In an attempt to optimize the serialization/deserialization process I simply made the class implement the ISerializable interface and wrote some optimized serialization routines

<serializable()>public MainClass
       implements ISerializable
....... 
end class

优化的作品真的很好，但我必须找到一个方法来reatrive里面的旧文件中的数据实现向后兼容。

The optimization works really well but I MUST find a way to reatrive the data inside the old files for backward compatibility.

我怎样才能做到这一点？

How can I do that??

皮耶路易吉

推荐答案

stmax 具有优良的答案，但我会实现它这个样子，它使用 SerializationEntry.GetEnumerator（ ）而不是的try / catch 。这种方式是更清洁，显著更快。

stmax has an excellent answer, however I would implement it like this, which uses SerializationEntry.GetEnumerator() instead of try/catch. This way is cleaner and significantly faster.

public MainClass(SerializationInfo info, StreamingContext context) {
    int version = 0;
    foreach (SerializationEntry s in info)
    {
        if (s.Name == "version") 
        {
            version = (int)s.Value;
            break;
        }
    }

    switch (version) {
      case 0:
        // deserialize "old format"
        break;
      case 1:
        // deserialize "new format, version 1"
        break;
      default:
        throw new NotSupportedException("version " + version + " is not supported.");
    }
}

我会preFER使用.FirstOrDefault（）LINQ的版本，但SerializationInfo中并没有实现IEnumerable - 在脸上，古怪的是，它甚至没有实现旧IEnumerable接口

I would prefer a LINQ version using .FirstOrDefault(), but SerializationInfo does not implement IEnumerable - in face, weirdly enough, it doesn't even implement the old IEnumerable interface.

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