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ASP.NET - ActionResult parameter is coming back null always when passing string - why?

Asked 2009-05-11T19:21:33.277
10

I am barely starting out with my first project on the ASP.NET MVC project type and I am creating a Details page where instead of passing the templated (int id), I would like to pass a string instead. But when I am in debug mode, and enter this in the URL, "myString" is null. Why so? Do I have to change anything else somehwere else?

So if I go to the URL and enter this:

http://localhost:2345/Bank/EmployeeDetails/3d34xyz

public ActionResult EmployeeDetails(string myString) // myString is null
{
     return View();
}
asp.net asp.net-mvc
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1 Answer

39

In you Global.asax.cs file, you will have the following route mapped by default:

routes.mapRoute(
    "Default",
    "{controller}/{action}/{id}",
    new { controller = "Home", action = "Index", id = UrlParameter.Optional });

That means that an url like http://localhost:2345/Bank/EmployeeDetails/3d34xyz will go to the Bank controller, the EmployeeDetails action and pass the value 3d34xyz into a parameter named id. It is perfectly alright to pass a string, but in order to make it work you have two options:

1) Rename the variable to id in your action method.

public ActionResult EmployeeDetails(string id) { ... }

2) Add another route that matches whatever name you want for your string. Make sure to make it more specific than the default route, and to place it before the default route in the Global.asax.cs file.

routes.mapRoute(
    "BankEmployeeDetails"
    "Bank/EmployeeDetails/{myString}"
    new { controller = "Bank", action = "EmployeeDetails", myString = UrlParameter.Optional });

This will pass a default value of null to myString if no value is passed in the url, but with the url you specified you will pass the value 3d34xyz.

answered 2009-05-11T19:29:49.583

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