How to call a Controller method from javascript in MVC3?

Question

Im using MVC3 architecture, c#.net. I need to compare text box content(User ID) with the database immediately when focus changes to the next field i.e., Password field. So I

Answer 1

See JQuery.get(), System.Web.Mvc.JsonResult.

For Example:

You'll need an action to catch the GET request:

public class HomeController
{
    [HttpGet]
    public ActionResult ValidateUserID(string id)
    {
        bool superficialCheck = true;

        return Json(new { success = superficialCheck },
            JsonRequestBehavior.AllowGet);
    }
}

A few points, in no particular order:

• Notice that the first parameter to .get is the matching URL to the controller action?
• The value of the #userID html field is appended to the end of the URL, allowing MVC to data bind it in to the action parameters ValidateUserID(string id).
• The Controller.Json method formats .NET objects as JavaScript objects. The formatted object is recieved by JQuery as data in the callback function.
• JsonRequestBehavior.AllowGet tells MVC that its okay to pass data back to the browser from a .GET.