What is best practice for passing parameters with RedirectToAction?

Question

I have a view with a form and HttpPost. When the model gets
passed to the action, I want to test a string, and then redirect to a different action.

So my solution was to do this:

[HttpPost]  
public IActionResult Privacy(UserStatusViewModel model)  
{  
    if (model.UserFound != null)  
    {  
        return RedirectToAction(nameof(Index), new { userstatus = model.UserFound });  
    }  
  
    return View(model);  
}  

public IActionResult Index(string userstatus = null)  
{  
    return View(model:userstatus);  
}  

This works, but I'm really uncomfortable with it. What would be the cleanest way to
perform the following steps:
a. Post to the Privacy action method
b. Do some tests
c. Based on the results, redirect to action method "Index" with a string?

I realize I could use ViewData, but I'm not cool on that either. I don't know what's bothering me!

Answer 1

Hi, @Coreysan

From your code, I think you just want to pass a string value to another view. And from your description of the question, You seems to think that use:

return RedirectToAction(nameof(Index), new { userstatus = model.UserFound });  

to redirect to HttpGet method of Index is a little bit not clean.

In my opinion, You can try this code:

[HttpPost]  
 public IActionResult Privacy(UserStatusViewModel model)  
 {  
     if (model.UserFound != null)  
     {  
         return View("Index", model.UserFound );  
     }  
      
     return View(model);  
 }  

This code will just return a string (model.UserFound) to Index view directly instead of redirecting to another action. I think it is cleaner than using return RedirectToAction(xx).

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Best regards,
Xinran Shen

Answer 2

a redirect can only pass data on the query string (you can not send post data with a redirect). a best practice is to encrypt keys and sensitive data. another best practice is to store the data on the server in a persistent store, and only pass a key (guid) to the data.