MVC 5 - RedirectToAction - Cannot pass parameter correctly - asp.net-mvc

Question

I have a method that looks as follows:
[Authorize]
public ActionResult Create(int? birdRowId, Entities.BirdSighting sighting)
{
...
...
}
I want to call the above method from another method in the same controller as follows:
[Authorize]
[HttpPost]
public ActionResult Create(Entities.BirdSighting birdSighting, FormCollection collection)
{
...
...
return RedirectToAction("Create", new {birdRowId = 10, sighting = birdSighting});
}
The RedirectToAction method calls the method correctly. And, the first parameter of the method being called (birdRowId) does equal 10. However, the second parameter, sighting, is always null, even though I'm passing an instantiated object with values. What am I doing wrong?

Answer 1

Remember, HTTP is stateless !
RedirectToAction method returns a 302 response to the client browser and thus the browser will make a new GET request to the specified URL.
If you are trying to follow the PRG pattern, I think you should not try to pass complex objects. You should only pass the ID of the resource so that the GET action can build the resource( the model) again using that ID.
return RedirectToAction("Created", "YourControllerName", new { #id=10} );
and in the Created action, read the id and build the object there.
public ActionResult Created(int id)
{
BirdSighting sighting=GetSightingFromIDFromSomeWhere(id);
// to do :Return something back here (View /JSON etc..)
}
If you really want to pass some data across (Stateless) HTTP Requests, you may use some temporary storage mechanism like TempData
Set your object to TempData in your HttpPost action method.
[HttpPost]
public ActionResult Create(BirdSighting birdSighting, FormCollection collection)
{
// do something useful here
TempData["BirdSighting"] =birdSighting;
return RedirectToAction("Created", "YourControllerName");
}
And in your GET action method,
public ActionResult Created()
{
var model=TempData["BirdSighting"] as BirdSighting;
if(model!=null)
{
//return something
}
return View("NotFound");
}
TempData uses Session object behind the scene to store the data. But once the data is read, the data is terminated.