Attempt to use DLL results in error - c#

I am using a library (DLL) that uses the Oracle.DataAccess DLL to connect to the database.
I am doing in in C# .NET framework 3.5
When I attempt to compile, the compilation takes place, but the executable throws this error message.
Could not load file or assembly 'Oracle.DataAccess, Version=2.111.7.20, Culture=
neutral, PublicKeyToken=89b483f429c47342' or one of its dependencies. An attempt
was made to load a program with an incorrect format.
Is there some way to get around this? What could be causing this to happen?

The dll for that ODBC is likely a 32bit only dll. Are you using this on a 64bit machine? If you are, IIS 7 has an option in the application pool that will allow you to "Enable 32-Bit Applications".

One possibility: Your programm is compiled with x64 or AnyCPU on a 64bit machine but the dll has been compiled with support for x86 only.
You can overcome this if you change the plattform of your Solution (or project) to x86.
I know you can force a 64bit Assembly to run as a 32bit app with:
corflags /32bit+ Oracle.DataAccess.dll
That works because the MSIL code is not bound to a processor architecture. However I never tried it the other way:
corflags /64bit+ Oracle.DataAccess.dll
so I can't tell if this works. And I propably won't work if the dll has unmanaged dependencies.

Related

"Could not load referenced assembly System.Core.dll"

Caught a BadImageFormatException saying
"Could not load file or assembly 'C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Core.dll' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded."
This is the error message that I get when I try to run my project. Can someone help me?
It looks like you are trying to load a .net framework dll from a project running .net 1.1. Either that or you have a mis-match in running a x86 app vs a 64 bit dll, or trying to run a x64 app against a 32 bit dll.
Check with architecture you are running, and the target framework of the application.

C# ODP.NET Load file or assembly

I recently started testing on a C# (4.0) app that uses ODP.NET (Oracle.DataAccess 4.112.3)
I set this project to target any platform and publish the app.
When I run the program on the client machine I receive:
Could not load file or assembly 'Oracle.DataAccess, Version=4.112.3.0,Culture=neutral,
PublicKeyToken=89b483f429c47342' or one of its dependencies. An attempt was made to load
a program with an incorrect format.
Like I said I've targeted 'Any CPU' and I've also embedded the Oracle.DataAccess assembly with the app.
I get this error on machines that have the Oracle client installed as well as machines that do not.
Any help is appreciated.
Like I said I've targeted 'Any CPU'
This is likely the problem.
The Oracle.DataAccess has separate versions for 32bit and 64bit systems. If you are developing on a 32bit machine, and then deploying on a 64bit OS, you will receive this message.
You could easily work around this by building your application to target x86, and deploying the 32bit version of the data access components.
As Reed Copsey said, there are two different DLLs. When you target ANYCpu, your app will run in 64 bit on a 64 bit machine, and 32 bit on a 32 bit machine. Therefore, if you want your app to work on 32 or 64 bit and run in AnyCPU mode, you should change the reference of Oracle.DataAccess to Specific Version=false and copy local = false. When you deploy to a client, they should have the oracle dll in the their GAC and it should pick up the correct version automagically.
You should perhaps check if the Oracle.DataAccess assembly has any dependencies in your machine and that it is missing in the client machine.
From debug Any cpu at top change the optin to debug X64, though internally Any CPu points to X64 only but that does not work, try to change it to x64 and it should work like a charm

FileNotFoundException (DLL not found)

I'm getting that strange error on one of client's machines. It throws FileNotFoundException, but that DLL is definitely right there in the folder with Executable.. Why it can't find it?
Please advise..
Psychic debugging, since you have not included the full exception details, is that you have a 32bit versus 64bit mismatch:
Your Executable is AnyCPU
The referenced DLL (or a downstream reference) is x86
The machine running the executable is 64bits
Basically, you'll have to recompile your C# executable with a Platform of x86 if you have any x86 DLL dependency (usually an unmanaged DLL).
The assembly may be missing one of its dependent assemblies.

How do I reference a 32 bit DLL in a 64 bit project?

I've got a C# 2.0 project which is set to target 'Any Cpu', however it is referencing a C++ project that's building a 32 bit dll.
When I try to run my program on a 64bit machine I get the following error:
System.BadImageFormatException was
unhandled Message: Could not load file
or assembly TreeTMHook,
Version=1.0.2889.19619,
Culture=neutral, PublicKeyToken=null
or one of its dependencies. An attempt
was made to load a program with an
incorrect format.
How can I fix this?
Update
I want to be able to keep the main project as any cpu.
Thanks.
You'll need to build your .NET project as 32bit (x86 target) if you want it to correctly load a 32-bit DLL on a 64bit machine.
RE: Update:
If you want to keep your project as "Any CPU", you'll need a 32bit and a 64bit version of the DLL, and make sure the appropriate version is distributed with your app. If you can't build the other project as 64bit, you must build your .NET project as 32-bit only.
You will have to force your EXE project to run in 32-bit mode so it can use that C++ DLL. Project + Properties, Build tab, Platform Target = x86.
You may want to take a look at this article it explains why it is not possible, in short since you are dealing with pointers when accessing unmanaged code.
To keep you main project as Any Cpu, you need to supply both 32 and 64 bit version of the .dll - which should be possible, seeing as you're building it from source.
You then need to supply the executable with a manifest pointing it toward to right dll verion depending on platform.
Please use .net reflection and consume objects and its methods. Instead of direct 32 bit dll reference.

Single x86-built Assembly Causing entire Assembly to execute as 32-bit

My program (a console application) references several other assemblies (many open-source libraries). I built the assembly with the "Any CPU" option set (using VS2008). When I start the assembly from a 64-bit command prompt on a Windows Server 2008 x64 machine the process always starts as a 32-bit process!
I looked through my references and it appears as though I have a reference for a 32-bit assembly referenced. Could this single reference cause the entire assembly to start as 32-bit?
Also, I use ILMerge to merge all of the referenced assemblies into a single assembly. Maybe that has something to do with it?
Could someone help me figure out what is going on here?
If you need to load a 32bit assembly, the entire process will need to be 32bit. You could target "Any CPU" for your main application, but then it will run 64bit, and fail at runtime when it tries to load the 32bit assembly.
ILMerge is smart enough to switch the main entry assembly from AnyCPU to x86 if you have an x86 assembly as part of your merge, to prevent this from being a problem.
If you want to run 64bit - you'll need to have all of the assemblies be 64bit or AnyCPU.
Yes, this is likely your problem. I would rebuild the assembly as "Any CPU".

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