Attempt to load Oracle client libraries threw BadImageFormatException.

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To all,

I know there is a solution to this problem on this website but it is not working for me.
I am new to web development and am probably doing something very basic wrong.
I am running Windows 7 64-bit and Visual Studio 2008.

I am porting a WPF application to a web application. The application uses Oracle Client to connect to the database. Upon connection (.Open()), it is throwing the error:

"Attempt to load Oracle client libraries threw BadImageFormatException. This problem will occur when running in 64 bit mode with the 32 bit Oracle client components installed."

I am running the web application on my desktop and not on a server at this point. The desktop application connects to the database fine and uses the 32-bit version of the OracleClient dll located in the folder:

Windows\Microsoft.NET\Framework\v2.0.50727

The IIS is set to this version (v2.050727) and Enable 32-bit applications is set to false.

I have tried using the 32-bit Oracle Client and the 64-bit version located:

Windows\Microsoft.NET\Framework64\v2.0.50727

I continue to get the same error.

If anyone can help, I would greatly appreciate it.

Thanks in advance,
Gloria

Posted 7-May-13 4:18am

Member 9454834

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Sergey Alexandrovich Kryukov · Answer 1 · 2013-05-07T04:31:00

Solution 1

You cannot mix the assemblies (or unmanaged modules) with different instruction-set architectures in a single process. Check up each and every module. Normally, if you build all the assemblies as "AnyCPU", the ultimate instruction-set architectures actually used during runtime will be defined by the actual architecture of the machine.

Note that on all 64-bit systems, 32-bit process will work via WoW64:
http://en.wikipedia.org/wiki/WOW64[^].

At the same time, different 64-bit architectures wull also conflict: x86-64 and Itanium (I-64).

I cannot imagine the situation when you might need the target instruction-set architecture other then AnyCPU in a Web application.

See also: http://en.wikipedia.org/wiki/Instruction_set[^].

—SA

Posted 7-May-13 4:31am

Sergey Alexandrovich Kryukov

v2

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Member 9454834 7-May-13 11:04am

Thanks for your quick response.
I checked the Configruation Manager and the project platform is set to 'AnyCPU'.
I switched the OracleClient assembly back to the 32-bit version and it does not work still.
All of the other assemblies are 'System.' assemblies and not home-grown assemblies. How do you check if they are set to 'AnyCPU'?

Sergey Alexandrovich Kryukov 7-May-13 11:10am

There should be something else which conflicts. When you say "System..." you probably mean the .NET Assemblies from FCL. They are put to GAC and are selected by a strong name with "automatically" correct target platform.

I don't know what conflicts, but there is something. Do one experiment: set everything to x86 and 32-bit and check up if it works. Of course, use 32-bit Oracle client...

—SA

Member 9454834 7-May-13 11:18am

Yes. By 'System' assemblies, they are the .NET assemblies.
I changed the Oracle Client to x86 by selecting the dll in the folder:
C:\Windows\Microsoft.NET\Framework\v2.050727

I get the same error...
{"Attempt to load Oracle client libraries threw BadImageFormatException. This problem will occur when running in 64 bit mode with the 32 bit Oracle client components installed."}

Can you think of anywhere else there can be a conflict?
Thanks

Sergey Alexandrovich Kryukov 7-May-13 11:29am

What do I see?! Do you really use the DLLs from C:\Windows\Microsoft.NET\Framework\v2.050727?!
This is the problem. Never do it! Assemblies are in GAC, you should add them by strong name, not by a location of the executable module.

Did you do such things before? Is so, let me give you some good news: you haven't done any programming, all you did was a complete mess.
You should reference GAC assemblies by strong names. Read:
http://en.wikipedia.org/wiki/Global_Assembly_Cache
http://en.wikipedia.org/wiki/Strong_name

Practically, with Visual Studuo, you should add references using the tab ".NET" of the "Add Reference" window, not "Browse".

—SA

Member 9454834 7-May-13 11:49am

I did that originally...
Went to the .NET tab and selected the OracleClient.
Only when I had trouble with the error that I looked deeper into what assembly was being added.
Looking to the path in the .NET tab, this is where the DLL is coming from:
Windows\Microsoft.NET\Framework\v2.050727.
Again, troubleshooting the problem, I found a folder for what I believe to be the 4-bit libraries (Framework64) and tried those and the problem still persists.

I am loading the same dll whether I go thru .NET tab or the Browse Tab.

There must be another conflict.

Sergey Alexandrovich Kryukov 7-May-13 12:09pm

Never ever link to those assemblies by location of their executable modules. Keep it agnostic to those directories.
—SA

Member 9454834 7-May-13 12:31pm

I removed the OracleClient reference and added it by going to the .NET tab and adding it that way.

The problem still exists.

As I stated in the original post. The WPF application uses this same reference and the connection works fine. I am using the Web Application locally and not on a web server at this time, until I get the basic functionality working. The only difference is that one application is a desktop and the other is a web app. I thought it had something to do with a configuration that I missed when creating the web app.

Any other suggestions or comments, especially if they are respectful, would be appreciated.

Sergey Alexandrovich Kryukov 7-May-13 14:24pm

Did do the experiment I advised? Another step is: isolate Oracle for a while. Make a project without Oracle to see if that was a problem.
One more thing: how to you host your Web site?
—SA

Member 9454834 7-May-13 15:03pm

Yes. I deleted the OracleClient reference and added it back using .NET tab and the problem still exists.
I made a project that just loads data from an xml file and it does not thru the oracle error.
Currently, I am running the web page locally and not hosting it on a server until I get most of the basic functionality working.

Sergey Alexandrovich Kryukov 7-May-13 15:15pm

I did not mean that. I meant to try some sample project not using Oracle at all...
Not hosting on a server... is not an answer. There is always a server. Do you mean you are using the Visual Studio development HTTP server? You should use one, no matter what you do...
—SA

Member 9454834 7-May-13 15:32pm

Yes. I am using the Visual Studio development server.
I created a project that does not use Oracle and did not have the error.

Sergey Alexandrovich Kryukov 7-May-13 16:12pm

OK, this is some result. No you can focus on having Oracle binding with target instruction-set architecture, everything else is correct. I actually kinda expected that.
Now, did you try all x86? will it work?
—SA

Member 9454834 7-May-13 16:20pm

Do you mean all assemblies as x86 or try Oracle assembly or something else?

Sergey Alexandrovich Kryukov 7-May-13 16:24pm

No, I meant, assuming that Oracle client is x86, set your assemblies as x86, just for experiment.
Ultimately, what you need is the x86-64 (or whatever you are using) Oracle client. All problem is localized to this module...
By the way, chances are, if your "read" Web hosting has everything properly installed, the problem will go by itself.
—SA

Member 9454834 7-May-13 16:36pm

I don't see how to set the specific assemblies to x86.
I went to the Configuration Manager and changed the project platform from 'AnyCPU' to 'x86'. I still get the same error.
I believe the Oracle Client is x86. It is the one selected in the .NET tab.