(C# ASP.NET Core) How to handle a FORM submit event

Recap of the FORM learnt so far

Please see the previous tutorial for continuity - (C# ASP.NET Core) Creating an HTML FORM with Razor Pages

We have learnt how the various fields of a [BindProperty] are connected to a form on a razor page. When the form is submitted, this same property contains the values filled and submitted by the user.

Video Explanation

Please watch the following youtube video:

Recommended Handler for a FORM POST
(see the linked video for details)

A form POST should be handled by an asynchronous OnPostAsync handler because a form POST is invariably processed through database updates and inserts, which must always be done asynchronously.

public class IndexModel : PageModel
{

  [BindProperty]
  public User UserData { get; set; }

  // asynchronous handler recommended 
  public async Task<IActionResult> OnPostAsync()
  {

    // "UserData" BindProperty (see above) 
    //  contains all the values entered by the user 

    // process them here 

    // . . . and redirect 
    return RedirectToPage( any parameters . . . );

  }


  // other members of the class . . . 
}

The [BindProperty] contains the posted data as can be seen in the breakpoint.