Unhandled exception : 'Could not load type 'S7.Net.Plc' from assembly 'S7.net, Version=1.0.0.0, Culture=neutral,

Question

Hello All,

I am facing an issue with this exception and need your support to resolve.

S7.Net.Plc' from assembly 'S7.net, Version=1.0.0.0, Culture=neutral,

I am creating a windows form using c# to make a connection between S7 300 PLC and this form . Hence I have insalled S7netplus package which is provided by Siemens to make the connection.

But as I run the Code I get this exception .

Answer 1

Hello @Yash89 ,

Welcome to Microsoft Q&A forum.

Please first try to remove NuGet cache by removing folders(packages) in C:\Users\username\.nuget\packages. After that remove the hidden .vs folder, bin and obj folders in your project folder, and rebuild your project.

If it doesn’t work, please try to run all commands mentioned here(Clearing local folders) to clean NuGet cache again and then rebuild your project.

Please also open this folder %windir%\Microsoft.NET\assembly and make sure that S7netplus package isn’t included in any three folders(GAC_32, GAC_64, GAC_MSIL).

Besides, may I confirm several information with you to check further:

1. Is your project based on .NET or .NET Framework? And could you share us the detailed version of the based framework for example .NET 7.0.
2. Is there any other project included in your solution? And is there any reference between projects?
3. Are you using the latest version of S7netplus package?
4. Did you install multiple versions of S7netplus package?
5. How did you use S7.Net.Plc in your project, is there any code snippet we can check further?
6. Does this issue appear in a newly created project?

Sincerely,

Tianyu

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