What is the "best" way to handle alternately Post and Get Actions?

Question

I am trying to build sth pretty simple, but I try to do it the correct way. But I struggle to figure out what is best.

I have a process chain where the user has to fill in some fields in different forms. Sometimes it depends from the user inputs which form the user is shown next.

[HttpGet]
public IActionResult Form1(Form1Vm f1vm)
{
   return View(f1vm);
}


[HttpPost]
[ActionName("Form1")]
public IActionResult Form1Post(Form1Vm f1vm)
{
   //process the data etc
   //prepare the new viewmodel for the next form view (f2vm)

   //Option1:
   return View("Form2", f2vm);

   //Option2:
   return RedirectToAction("Form2", f2vm); 
   //for Option 2 I would need an additional HttpGet Action Method in which I 
   //would have to call Modelstate.Clear(); in order to not have the 
   //immediate validation errors on page load
   //also all the properties of my viewmodel are passed as get parameters
   //what looks pretty nasty for me
}

//More form views action methods should be added here...:

What is the better way? As mentioned in my comments above I have quite a big disadvantage for using the RedirectToAction option. However if I use the direct View(); call, I don't take care on https://en.wikipedia.org/wiki/Post/Redirect/Get and the user cannot simply refresh a page without getting a warning that his form is submitted once again.

Do I miss another way or don't see something obvious?

Edit: I just thought about a 3rd way, which I have seen quite often: Not transfering the whole VM to a HttpGet method but only the ID. I'd then have to load all the data stored previously directly from the db, map it again to my new VM and then call the View(); with this VM. Right now I think this is the "best" solution, however I feel like it is pretty laborious...

Answer 1

As per the dicussions, I would suggest using depending on your preference :

1) Save to db at the end of each form post and as you suggested use the I'd to redirect to a GET. 2) Depending on the the number of form pages and your requirements, retrieving values that a form needs on the get would be standard practice. This ensures that if a user drops off a form at any stage you can then start them off where they left off. 3) I wouldn't setup the viewmodel for the next form in the post of the previous. Generally as part of the single responsibility principle you want to ensure that your methods have only one reason to change. 4) PostRedirectGet pattern should be implemented with this to ensure data is not saved multiple times if a user refreshes after a post.