Is it possible to use GridView in VBA?
The simple answer is "No", or "Yes", depending on whether you use 84-bit AutoCAD, or still 32-bit AutoCAD (option for pre-AutoCAD2020), but most likely, "No" is the answer: who is still using 32-bit AutoCAD these days? It also depends on if you could find a third party 64-bit activeX GridView control (I bet you probably won't). You basically is stuck with the built-in UI controls.
Lack of UI and other component support of 64-bit VBA makes it not worth for developing CAD application that is beyond simple/quick CAD fix/solution. If the solution needs better/complicated UI functionality, or is mission-critical, using VBA at this point of time is not a wise choice. I'd not waste my time/effort on VBA unless the business asks a quick solution and I can get it done in a day, or two at most. If you are developing serious CAD solution, moving on to AutoCAD .NET API development would be the way forward.
If I understand you correctly, by GUI, you mean the GUI run inside AutoCAD, not an external app. As I said, because now AutoCAD VBA aer 64-bit, its GUI support is extremely limited (if you knew that Acad VBA almost died in version 2014, and only survived that MS eventually supplied Autodesk 64-bit VBA).
So, if you continue on using VBA, no GridView, no listview, no treeview. If you want to build better UI into your application, you need to move away from VBA and learn to use AutoCAD .NET API. You can choose either C# or VB.NET (do not listen to your temptation to choose VB.NET just because its code syntax is much more close to VBA code. Again, it would be another bad choice you would regret soon).
Even you may have been fairly familiar with AutoCAD programming with VBA (thus AutoCAD COM API), you would still face quite steep learning curve: you need to be knowledgeable enough on generic MS .NET programming before tackle AutoCAD .NET API.
There are many Youtube videos available for AutoCAD .NET programming for beginner, if you search "AutoCAD .NET Programming" in Youtube.
You can download Acad .NET programming labs here(step by step of 9 labs) to get started.
As for <CommandMethod...>, that is how you run your .NET application, just as you do with VBA: if you want to run VBA code, you need to run VBA macro, as if it is a command. So, what is wrong by using command to start your application? .NET API could also provide way to run code automatically, such as: as long as the DLL is loaded, the code can run; or the code can be triggered by certain events... But run a command is just a most normal/common way to let AutoCAD do something, be it .NET command, or built-in command, or LISP/VBA command/macro. You'll figure it out why all the tutorial begins with a simple command "Hello World" once you get familiar with .NET API.
Once you have gone through the 9 basic labs and think you are ready to jump into a real development task, you can ask questions in .NET forum, be it basic ones, or advanced ones.
Well, as I recommended, you should patiently go through the labs. If you want to watch video for quicker learning, simply search Youtube for "AutoCAD .NET API programming", which would give you tons of short or long clips, mostly for beginners.
As far as I know, adding GUI to AutoCAD .NET app is very, very similar, or almost the same, to what to do with Inventor. For Inventor you use its COM API, event the development tool is .NET. However, this would not change the way you add GUI part in the project. In terms of easiness of adding GUI in the Visual Studio project (the GUI being WinForm, or WPF), Inventor, or AutoCAD, they are in the same level.
