Question

I have a post action Import:

public ActionResult Import()
{
    var fileNames = new List<String>();

    foreach (string path in Directory.GetFiles(directoryPath))
    {
        //do a whole bunch of stuff
        ...
        fileNames.Add(path.Split('\\').Last());            
    }

    return RedirectToAction("Index", new { InvalidFiles = fileNames });
}

As you can see, it redirects to an Index action, passing the List<String> of file names

public ActionResult Index(List<String> InvalidFiles)
{
    return View();
}

In the Index action, the List comes in with the right amount of elements, however all the actual strings has been changed from the filename to the string “System.Collections.Generic.List`1[System.String]”.

Any idea why this is happening? Is there a better way to pass the list to the new action, possibly using TempData?

Answer 1

You can use TempData to temporally hold the data between actions.

public ActionResult Import()
{
    var fileNames = new List<String>();

    foreach (string path in Directory.GetFiles(directoryPath))
    {
        //do a whole bunch of stuff
        ...
        fileNames.Add(path.Split('\\').Last());            
    }

    TempData["fileNames"] = fileNames;

    return RedirectToAction("Index");
}


public ActionResult Index()
{
    var invalidFiles = TempData["fileNames"] as List<String>;

    return View();
}