为什么我们不能序列化这些对象？
为什么我们不能将对象序列化为随机访问文件？另一方面，我们可以将对象序列化为顺序访问文件？
""C# 不提供在运行时获取对象大小的方法。这意味着， 如果我们序列化该类，我们无法保证固定长度的记录大小“”（来自我读到的书）。
所以我们无法读取随机访问文件，因为我们不知道文件中的每个对象大小，所以我们如何才能进行查找??????
why we can't Serialize objects into Random Access file ? and on the other hand we can serialize objects into sequential access file ?
""C# does not provide a means to obtain an object’s size at runtime. This means that,
if we serialize the class, we cannot guarantee a fixed-length record size "" (from the book that i read in).
so we cannot read the the random access file because we don't know every object size in the file so how we could do seeking ??????
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任何标有 SerializedAttribute 属性的对象都可以序列化（在大多数情况下）。序列化的结果始终定向到流，该流很可能是文件输出流。
您是否在问为什么对象图不能部分反序列化？ .NET 序列化仅[反]序列化完整的对象图。否则，您将不得不转向其他序列化格式化程序，或编写自己的序列化格式化程序。
要直接随机访问文件，必须使用支持查找的流打开文件。
编辑：
从序列化中寻找结果流没有实际目的 - 只有序列化格式化程序知道其中有什么，并且应该始终在流的开头提供。
用于将数据持久保存到其他结构中；分两个阶段进行：首先，将序列化字节定位到一个[即内存支持]流，您可以随后从中读取大小，然后使用所述大小知识将数据写入实际的后备存储。
您无法预测序列化对象的大小，因为序列化表示可能与运行时表示有很大不同。
如果您仅使用原始类型，并且使用 BinaryWriter 进行编写，那么仍然可以实现对输出大小的精确控制 - 但这本身并不是序列化。
Any object marked with the
SerializableAttributeattribute can be serialized (in most scenarios). The result from serialization is always directed to a stream, which may very well be a file output stream.Are you asking why an object graph cannot be deserialized partially? .NET serialization only [de]serializes complete object graphs. Otherwise you'll have to turn to other serialization formatters, or write your own.
For direct random access to a file, you must open the file with a stream that supports seeking.
EDIT:
Seeking in the resulting stream from a serialization has no practical purpose - only the serialiation formatter knows what's in there anyway and should always be fed the very start of the stream.
For persisting the data into other structures; do it in a two-stage process: First, target the serialization bytes to a [i.e. memory-backed] stream that you can read the size from afterwards, then write the data to the actual backing store, using said knowledge of size.
You can't predict the size of a serialized object, because the serialized representation might differ a lot from the runtime representation.
It it still possible to achieve exact control over output size, if you use only primitive types, and you write using a BinaryWriter - but that is not serialization per-se.
.NET 中默认的二进制序列化会序列化整个对象图，由于其图的本质，它没有恒定的大小，这意味着每个序列化对象（记录）不会有恒定的大小，从而防止随机访问。
为了能够随机访问文件中的任何记录，请编写您自己的类的二进制序列化实现，或使用数据库。如果您需要一个简单的、免安装的单线程数据库引擎，请查看 SQL Server Compact。
The default binary serialization in .NET serializes a whole object graph, which, by its nature of being a graph, doesn't have a constant size, which means each serialization object (record) won't have a constant size, preventing random access.
To be able to randomly access any record in a file, write your own implementation of the binary serialization of your class, or use a database. If you need a simple, no-install single-threaded database engine, have a look at SQL Server Compact.