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Assembly.LoadFrom failing in .NET 2.0

Author
7 Jul 2006 3:18 PM
John H
Hi,

We have an application that generates .NET assembly DLLs at runtime and
executes them. It normally generates the assembly DLL once per user
task and any time the same user task is done again it simply loads the
already existing DLL and executes it.

We are using the .NET Code DOM to compile the .NET DLLs and then using
reflection to call them.

This is working fine in .NET 1.1, however on a machine with .NET 2.0
installed we are getting different behaviour.



The code does the following:

            Call Assembly.LoadFrom() to determine if DLL is generated

            If (call Failed)

{

                        Generate DLL and save to hard disk

                        Get Assembly from
CompilerResults.CompiledAssembly

            }

            Execute method on generated Assembly DLL



When using .NET 2.0 the Assembly.LoadFrom() call fails correctly the
first time and then generates the DLL successfully. However, the
assignment of CompilerResults.CompiledAssembly fails even though the
DLL is now created. Any further calls to Assembly.LoadFrom() for the
same DLL in the same process also fail, they return the error "Failed
to load DLL or one of it's dependencies".

However, when I then stop and start the process the Assembly.LoadFrom()
calls work.



It seems that the fact that the first Assembly.LoadFrom() call failed
is cached in the current process and any subsequent calls to load the
same DLL automatically fail.

Is this a change in .NET 2.0?

Is there a way around this?



Thanks for any help you can give,

                                    John.

Author
13 Jul 2006 2:40 PM
John H
Hi,
In case anyone is interested got an answer on

http://discuss.develop.com/archives/wa.exe?A1=ind0607a&L=advanced-dotnet
It's the second one from the top.

It appears to be due to a change/bug introduced into LoadFrom in .net
2.0

John




John H wrote:
Show quote
> Hi,
>
> We have an application that generates .NET assembly DLLs at runtime and
> executes them. It normally generates the assembly DLL once per user
> task and any time the same user task is done again it simply loads the
> already existing DLL and executes it.
>
> We are using the .NET Code DOM to compile the .NET DLLs and then using
> reflection to call them.
>
> This is working fine in .NET 1.1, however on a machine with .NET 2.0
> installed we are getting different behaviour.
>
>
>
> The code does the following:
>
>             Call Assembly.LoadFrom() to determine if DLL is generated
>
>             If (call Failed)
>
> {
>
>                         Generate DLL and save to hard disk
>
>                         Get Assembly from
> CompilerResults.CompiledAssembly
>
>             }
>
>             Execute method on generated Assembly DLL
>
>
>
> When using .NET 2.0 the Assembly.LoadFrom() call fails correctly the
> first time and then generates the DLL successfully. However, the
> assignment of CompilerResults.CompiledAssembly fails even though the
> DLL is now created. Any further calls to Assembly.LoadFrom() for the
> same DLL in the same process also fail, they return the error "Failed
> to load DLL or one of it's dependencies".
>
> However, when I then stop and start the process the Assembly.LoadFrom()
> calls work.
>
>
>
> It seems that the fact that the first Assembly.LoadFrom() call failed
> is cached in the current process and any subsequent calls to load the
> same DLL automatically fail.
>
> Is this a change in .NET 2.0?
>
> Is there a way around this?
>
>
>
> Thanks for any help you can give,
>
>                                     John.

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