Hi @AmitPatel-5670,
What is the target framework of your project?
Please provide more information about your adding ADO.Net Entity Data Model and your project.
Best Regards,
Daniel Zhang

Hi @NiranjanKumarGopalan-3044,
What version of your Visual Studio? As karenpayneoregon said, the Windows Forms Designer for .NET Core projects is currently available as a preview.
More details please refer to this document.
Best Regards,
Daniel Zhang

Hi @NiranjanKumarGopalan-3044,
This means that this feature is not yet supported in .Net Core, you can refer to karenpayneoregon's answer. Use the “Send Feedback” icon in Visual Studio top-right corner as shown in the following image and specify that it is related to the "WinForms .NET Core" area.
Best Regards,
Daniel Zhang

Hi @SamsonZeng-1320,
In order to find the cause of the problem more accurately and quickly, please provide some relevant codes to reproduce the problem and point out the specific code that caused the error.
Best Regards,
Daniel Zhang

Hi @SamsonZeng-1320,
As document said, support for some project types changes over time. A newer version of Visual Studio might not support certain projects at all, or it might require that you update a project so that it's no longer backwards-compatible.
The newly created project is new and contains all the necessary things. The old project may have some things that the new version needs but does not have.
Best Regards,
Daniel Zhang

Hi @John-1477,
May I know if you have got any chance to check my answer? I am glad to help if you have any other questions.
Best Regards,
Daniel Zhang

Hi @HemanthB-9452,
Please feel free to contact us if you have other questions.
Best Regards,
Daniel Zhang

Hi @HemanthB-9452,
I have not heard from you for a couple of days. Please let me know if there is anything that I can help here.
Best Regards,
Daniel Zhang

Hi @DanXiao-7645,
May I know whether your issue has been solved or not? If not, please share it in here. We can work together to figure it out.
Best Regards,
Daniel Zhang

Hi @SaraLane-2191,
>> but he seems like he's talking about version 1.4.0 of ML.NET, and I'm using version 1.6.0.
What he means is that a code example is provided for the 1.4.0 version of ML.NET, you can change it to your own 1.6.0 path.
And do you still get the same error after trying the suggestions?
You can try to use the .NET Framework version 4.7.2 or higher.
Best Regards,
Daniel Zhang

Hi @SaraLane-2191,
You can try to use .NET Framework 4.7.2 or higher to rule out the possibility caused by the lower version.
For question about ML.Net, I suggest you ask this question here and you can get more professional answer.
Best Regards,
Daniel Zhang

Hi @NagendraKanvapuri-2769,
I saw raspy provided a detailed explanation here.
Best Regards,
Daniel Zhang

Hi @JeongeunLee-9751,
I saw that Castorix31 provided a detailed solution in another thread, did it solve your problem?
Best Regards,
Daniel Zhang

Hi @WanyamaEdwin-1498,
May I know whether your issue has been solved or not? If not, please share it in here. We can work together to figure it out.
Best Regards,
Daniel Zhang

Hi @WONGTony-4228,
I have not heard from you for a couple of days. Please let me know if there is anything that I can help here.
Best Regards,
Daniel Zhang