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And so, what would happen when you serialize the data in the program of v2 and will try to
deserialize them in the program of v1?

You get an exception:

System.Runtime.Serialization.SerializationException was unhandled
Message=The ObjectManager found an invalid number of fixups. This usually indicates a problem
in the Formatter.Source=mscorlib
StackTrace:
at System.Runtime.Serialization.ObjectManager.DoFixups()
at System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler
handler, __BinaryParser serParser, Boolean fCheck, Boolean isCrossAppDomain,
IMethodCallMessage methodCallMessage)
at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream
serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain,
IMethodCallMessage methodCallMessage)
at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream
serializationStream)
at Microsoft.Samples.TestV1.Main(String[] args) in c:\Users\andrew\Documents\Visual Studio
2013\Projects\vts\CS\V1 Application\TestV1Part2\TestV1Part2.cs:line 29
at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback
callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()

Why?

The ObjectManager has a different logic to resolve dependencies for arrays and for reference and
value types. We added an array of new the reference type which is absent in our assembly.

When ObjectManager attempts to resolve dependencies it builds the graph. When it sees the
array, it can not fix it immediately, so that it creates a dummy reference and then fixes the array
later.

And since this type is not in the assembly and dependencies can’t be fixed. For some reason, it
does not remove the array from the list of elements for the fixes and at the end, it throws an
exception “IncorrectNumberOfFixups”.

It is some ‘gotchas’ in the process of serialization. For some reason, it does not work correctly only
for arrays of new reference types.

A Note:
Similar code will work correctly if you do not use arrays with new classes

And the first way to fix it and maintain compatibility?

• Use a collection of new structures rather than classes or use a dictionary(possible classes),
because a dictionary it’s a collection of keyvaluepair(it’s structure)
• Use ISerializable, if you can't change the old code

Read Binary Serialization online: https://riptutorial.com/csharp/topic/4120/binary-serialization

https://riptutorial.com/ 108