isual Studio 2008 - System.numerics.dll not recognised as namespace in my VB code

Question

Hi, I was told to ask my question here in a previous answer from https://answers.microsoft.com/en-us/windows/forum/windows_11-wintop_apps-win_subtopwinapps/visual-studio-2008-systemnumericsdll-not/dbb0e8b0-4951-4897-a725-4cfa6ca7d9d0?messageId=9410e5bc-b9b4-465a-bf59-732c2f51095e

I managed to download Systems.numerics.dll file from URL https://www.dllme.com/dll/files/system_numerics. Then I added it as a reference in my project solution. I saw an error message in my Visual Studio project Module.bas "Warning 8 The referenced component 'System.Numerics' could not be found." even when I added the reference.

The Import System.Nurmerics is not recognised. I thought if I downloaded and installed .NET 4.8 from here - Downloaded and installed .NET 4.8 from

here (https://dotnet.microsoft.com/en-us/download/dotnet-framework/thank-you/net481-web-installer"dotnet.microsoft.com"))"dotnet.microsoft.com") it would make difference but no.

Is there a way to make this work? I need system numerics so I can use the complex number functions for my project. Any help with this will be greatly appreciated. Thanks in advance!

Answer 1

Please do not ever download system files from some arbitrary website and try to use them. This is generally just asking for malware to be added to your system. If you downloaded System.Numerics from some website then remove all references to it from your filesystem and then run a virus scan to ensure you didn't infect your computer.

System.Numerics is not supported by NET 3.5 so you cannot use it. It doesn't matter whether you copy files or not, it won't work. You need to target at least .NET v4. For .NET 4 you need to use at least .NET 4.6.2 as this is the earliest version that is still supported as discussed here. However if you are running Windows 10 or 11 then go ahead and target .NET 4.7.2 or higher as it ships with the OS. In general you do not need to install NET Framework as it is already installed by the OS. Which version you have depends on the version of the OS you are running.

VS 2008 is not supported anymore and doesn't support NET 4 anyway. Therefore you cannot use the System.Numerics assembly with VS 2008. VS 2022 Community edition is freely available so you should go ahead and install it instead. It'll support .NET 4 and all newer versions, that are still in support. However you may run into an issue trying to open an older VS 2008 project in the newer VS edition. You may have to recreate your project(s).

The changes between NET 3.x and NET 4 are huge. You will not be able to simply recompile your code to get it to work. The configuration settings and overall behavior are different. Your best bet is to create a new project with NET 4.x in VS 2022 and then copy over your legacy code piece by piece to rebuild your functionality. Be especially careful with any config file stuff as the NET 3.x configuration file won't work with NET 4.x. There are lots of articles online on how to do this.

Once you have your project loaded in VS 2022 with NET 4.x then you are reading to add support for numerics. In VB an Import statement doesn't control what assemblies are referenced (see here). It specifies what namespaces (a coding thing) are available to the current source file. Each source file must specific what namespace(s) it will use. The Import statement does that. In order for you to import a namespace you must have a reference, in your project, to an assembly that contains something in that namespace.

To add a reference to an assembly in your project, so you can import the namespace, go to the References node in Solution Explorer (or project properties if yo uprefer) and add an assembly reference to System.Numerics. It is already installed on your machine, just add an assembly reference to it (VS will show you the only one that is available to you). Then the namespace will be available and your Import, in the source file, will bring into scope the types available in that namespace.

Answer 2

Hi. Thanks for replying. I response I have added some attachments in answering;

1. How you added the dll file. The attachments go through how i did this in my current project. I had a copy of the system.numeric.dll within my projects folder.

System Numerics Issue for Microsof Q and A Forum - 0.jpg

System Numerics Issue for Microsof Q and A Forum - 1.jpg

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1. How you added/imported it to your project to use it - My last 2 attachments show that I tried to use the Imports System.Numerics command line at the top of my module with the error message I get when it cannot be found.
2. My Project is based on the .NET 3.5 Framework. I tried to get .NET 4.5 but i get a message saying its already part of my Windows 11 OS. Rebuilding my project does not remove the warning regarding system numerics.System Numerics Issue for Microsof Q and A Forum - 5.jpg

I hope what i have given you helps. I don't have vs 2022 but may try to get it if I can't use system.neumerics in VS 2008.

Thanks in advance!

Answer 3

Hi. I read your last comment. I am not stupid and have Antivirus and Maleware Bytes running on my PC at all times to prevent any malware. I will get VS 2022 and if necessary create a new project. I have done this before no problem. I wont bother you no more on this matter!!