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  1. Forum
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  7. .NET Core on Windows
  9. Could not load file or assembly

Could not load file or assembly

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11 Jun 2022 10:09 #10964 by support
Replied by support on topic Could not load file or assembly
Hello.

Unfortunately I do not quite understand what you wrote: "In the library I am using the NuGet package OpcLabs.QuickOpc (5.62.456). In order to use the library in my service I had to install the NuGet package (5.62.456) as well.". This seems to be a 3rd version you mentioned already. If you have installed OpcLabs.QuickOpc 5.62.456 consistently in your solution, and you are getting the error message the mentions " 'OpcLabs.EasyOpcForms, Version=5.63.232.1", then there is a version mismatch somewhere and you need to look around your solution/system to figure out where it comes from.

Regarding "I'm not sure if the exception is handled internally.": Does the exception crash your program, or are you just observing it in the debug output or breaking on it being thrown in the debugger?

Regards

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10 Jun 2022 11:59 #10963 by saratalley
Replied by saratalley on topic Could not load file or assembly
I am currently running a windows service that uses a custom library that implements the OPC client. In the library I am using the NuGet package OpcLabs.QuickOpc (5.62.456). In order to use the library in my service I had to install the NuGet package (5.62.456) as well.

I'm not sure if the exception is handled internally.

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10 Jun 2022 07:49 #10962 by support
Replied by support on topic Could not load file or assembly
In addition, please clarify which version of QuickOPC you are using (or trying to use).

There is some mismatch in what you provided - and it can actually be the cause of the problem.

You wrote " I tried running the examples from the QuickOPC 2020.3". But the error message lists version 5.63.232.1, which is for QuickOPC 2022.1.

Best regards

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10 Jun 2022 07:46 #10961 by support
Replied by support on topic Could not load file or assembly
Hello.

I need some clarification. Here are three cases that you might be describing, and I do not know which one it is:

1. If you are really trying to use our Windows Forms-related features in .NET Core/.NET 5+ project: This is currently not supported, and it is not going to work. .NET Core projects with current QuickOPC should not reference the BaseLibForms or EasyOpcForms assemblies.

What kind of project do you have? (console app, WinForms app, WPF app, Web app, Web service, Windows service, etc.)?

2. If you are not trying to use our Windows Forms-related features : I understand that the exception is thrown, but is it unhandled? This kind of exception, if it is thrown but internally handled in QuickOPC would be OK, per design.

3. If you are not trying to use our Windows Forms-related features, and the exception is not just thrown but also unhandled in QuickOPC (i.e. you have to handle it, and/or it actually crashes your program): Only this would be a problem that we need to look at.

Please let me know.

Best regards

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10 Jun 2022 00:34 #10960 by saratalley
Could not load file or assembly was created by saratalley
I have a .NET core application in VS 2022 that will run as a service, I'm currently debugging in the console. I get this exception when trying to run: Exception thrown: 'System.IO.FileNotFoundException' in System.Private.CoreLib.dll
Could not load file or assembly 'OpcLabs.EasyOpcForms, Version=5.63.232.1, Culture=neutral, PublicKeyToken=6faddca41dacb409'. The system cannot find the file specified.

I have verified that .dll exists in the bin folder. I get the error for platforms of Any CPU or x86. A colleague of mine copied my project and can run with no error. I tried running the examples from the QuickOPC 2020.3 and also get the same error.

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