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Using EasyDAClient and EasyUAClient in the same project

22 May 2019 06:24 #7413 by support
The App_Web_* assemblies are truly needed, but if everything worked as it should, they should not have to be referenced from your project. They are referenced from the EasyOpcClassic assembly, and therefore every project that references EasyOpcClassic should get them as well. But they need not to be referenced because there are no types form these assemblies that you yourself in your project need to utilize.

The assemblies are so-called mixed-mode assemblies, which contain both native and managed code. Not every tool is fully prepared to handle them. I am aware that problems sometimes occur. This usually means that the assemblies are not copied to the target directory of the project, even though they should. I have no solution for it, just workarounds.

Rather than referencing the assemblies, I recommend to copy them over to their proper places (e.g. custom build step or the like).

I suppose the issue with running unit tests is the same or similar.

In contrast with the topic title chosen, the issue does not have to do with "combining" OPC UA and OPC Classic. at least to my knowledge. It would be the same without OPC UA too.

Best regards

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22 May 2019 05:54 #7412 by

We are currently trialing EasyOpc in our product as means of allowing our clients to exchange data between their OPC servers our service. The clients will be using DA and UA OPC servers. After much trial and error we have a test project that proves we can communicate with at least two simulation OPC servers. But there are problems:
  • To communicate using EasyDAClient we need to add and reference the DLLs App_Web_OpcLabs.EasyOpcClassicRaw.amd64.dll and App_Web_OpcLabs.EasyOpcClassicRaw.x86.dll. Not having the DLLs results in error "FileNotFoundException: Could not load file or assembly 'App_Web_OpcLabs.EasyOpcClassicRaw.amd64, Version=5.54.1151.1, Culture=neutral, PublicKeyToken=6faddca41dacb409' or one of its dependencies. The system cannot find the file specified.
    + It is possible that Microsoft Visual C++ Redistributable Package is not installed."
  • Running unit tests that reference IEasyDAClient result in the error "Message: System.IO.FileLoadException : Could not load file or assembly 'OpcLabs.EasyOpcClassic, Version=, Culture=neutral, PublicKeyToken=6faddca41dacb409' or one of its dependencies."

The c++ redistributable is installed on my machine.

I have attached our test project that works but I don't want to reference DLLs as they will stop working if the nuget package is updated.

Can you offer any advise on what is not working here or suggest a better approach?


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