Assembly.Load() followed by Assembly.LoadFrom()?

Instanciation dynamique d'instance de type par chaine de caract?re | hilpers

Instanciation dynamique d'instance de type par chaine de caract?re | hilpers — Thu, 22 Jan 2009 19:08:29 GMT

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re: Assembly.Load() followed by Assembly.LoadFrom()?

Leon — Fri, 29 Jul 2005 00:41:55 GMT

Thank you for the book. I haven't seen that title before.

re: Assembly.Load() followed by Assembly.LoadFrom()?

Junfeng Zhang — Fri, 29 Jul 2005 00:37:18 GMT

It could be some mistake in your code. I can't really tell from this thread so far.

It could be a bug in CLR but this is very unlikely. Otherwise SQL folks will be chasing my back every minutes:)

Please report it in MSDN feedback center.

re: Assembly.Load() followed by Assembly.LoadFrom()?

Leon — Fri, 29 Jul 2005 00:23:53 GMT

I saw from the docs:

"Remarks
The common language runtime resolves references using the following set of guidelines.

First, it consults the list of assembly references returned by GetNonHostStoreAssemblies.

If the assembly appears in the list, the runtime binds to it normally.

If the assembly does not appear in the list, and the host has provided an implementation of IHostAssemblyStore, the runtime calls IHostAssemblyStore::ProvideAssembly to allow the host to supply the assembly to bind to.

Otherwise, the runtime fails to bind the assembly.

If the host sets ppReferenceList to NULL, the runtime first probes the Global Assembly Cache, then calls ProvideAssembly, then probes the application base, to resolve an assembly reference.

Note: The runtime calls GetNonHostStoreAssemblies only once, upon initialization. It is not called again."

But I don't see loader consulting list of assembly references returned by GetNonHostStoreAssemblies for assembly specified in ExecuteInDefaultAppDomain. But it is consulted when I return ppReferenceList = NULL; from GetNonHostStoreAssemblies. So, I'm just trying to find out if this a bug or not.

re: Assembly.Load() followed by Assembly.LoadFrom()?

Leon — Fri, 29 Jul 2005 00:20:01 GMT

But what I'm seeing is that ICLRAssemblyReferenceList is not consulted for the assembly specified in ExecuteInDefaultAppDomain when I return valid ICLRAssemblyReferenceList pointer from GetNonHostStoreAssemblies. And is consulted when I return null for ICLRAssemblyReferenceList pointer. This is on Beta 2.

It will be time consuming to create a repro sample for this if it's not a bug, but standard behavior. Otherwise I could report it.

re: Assembly.Load() followed by Assembly.LoadFrom()?

Junfeng Zhang — Thu, 28 Jul 2005 23:59:20 GMT

We call IHostAssemblyStore::ProvideAssembly when the assembly is *not* in the list of GetNonHostStoreAssemblies.

When GetNonHostStoreAssemblies returns NULL, we probe GAC, then IHostAssemblyStore, finally appbase.

There is a Matrix our test team uses. I'll see if I can still find it.

re: Assembly.Load() followed by Assembly.LoadFrom()?

Leon — Thu, 28 Jul 2005 23:47:38 GMT

Thank you for the book recomendation. I will buy it. I'm pretty familiar with how it works in .NET 1.1. I hope the book covers new hosting API/AssemblyStore and my question.

But briefly could you please just say if what I'm seeing is normal?

Assembly specified in ExecuteInDefaultAppDomain doesn't go through IHostAssemblyStore::ProvideAssembly when I return my own ICLRAssemblyReferenceList implementation. And does go through IHostAssemblyStore::ProvideAssembly when I don't return ICLRAssemblyReferenceList implementation in GetNonHostStoreAssemblies.

re: Assembly.Load() followed by Assembly.LoadFrom()?

Junfeng Zhang — Thu, 28 Jul 2005 23:28:47 GMT

You need to read Steven's book on this

http://blogs.msdn.com/junfeng/archive/2005/06/17/430342.aspx

It is a big topic.

re: Assembly.Load() followed by Assembly.LoadFrom()?

Leon — Thu, 28 Jul 2005 23:17:14 GMT

Thank you for the comments.

Would you mind answering CLR hosting and assembly binding relatedt questions?

I'm trying new CLR 2.0 hosting API.

1. I've provided IHostAssemblyManager impl to CLR.
2. I'm calling ExecuteInDefaultAppDomain(assemblyPath,...)

Now the questions is:

Why when I implement GetNonHostStoreAssemblies and return ICLRAssemblyReferenceList implementation, ExecuteInDefaultAppDomain fails to find the assembly. But if I set *ppReferenceList = NULL; in GetNonHostStoreAssemblies, it calls IHostAssemblyStore::ProvideAssembly.

Neither IHostAssemblyStore::ProvideAssembly/ICLRAssemblyReferenceList::IsAssemblyReferenceInList/LRAssemblyReferenceList::IsStringAssemblyReferenceInList are called when it fails for ExecuteInDefaultAppDomain. But they are called for example when CLR needs to find my custom AppDomainManager. Is this a bug or standard behavior for ExecuteInDefaultAppDomain?

Thanks a lot!

re: Assembly.Load() followed by Assembly.LoadFrom()?

Junfeng Zhang — Thu, 28 Jul 2005 19:53:00 GMT

1. No it will not be shared.

2. IHostAssemblyStore does not provide any advantage here. It is meant for SQLServer type of storage where the assembly physically exists in a database as bytes.