可以从ASP.NET控制器查看JSON对象

Question

I have a situation where a when a web page is accessed a controller action runs which retrieves the data for that page based on a user selection. I am attempting to send the data back to the page as a JSON object, however, the data opens up as one large string in an HTML page. The controller action, in a nutshell, looks like the following snippet:

Public JsonResult MyMethod(string userSelection)
{

    string userData = (string) Data;
    return Json(userData, “text”, JsonRequestBehavior.AllowGet);
}

I first tried to use the JQuery $.getJson() method but I think this is wrong as I believe it issues another call to the action method for the data, which is not what I want to do. What I want is to access the JSON object in JavaScript code so I can use the property data to populate fields on the web page. The basic question is what must I do in my JavaScript to receive the JSON object when the page is first rendered? I apologize if I am missing something fundamental; this is my first try.

Answer 1

I still had no luck today but when I left work I came up with a strategy walking to my car. A user makes a selection from a page that presents a list prior to entering the page on which I cannot figure out how to work with JsonResult. Part of the problem is the user selection contains a link that calls the controller/action that returns the JsonResult which conflicts with using $.getJson() within the page where I want to work with JsonResult. So here is my strategy: When the user makes the selection that brings them to the (problematic) page, I will call a controller/action that strictly works with (ASP) ViewData, and use the ViewData to initially present that page. Once on the page, the user can change the selection -- I will handle this with a JavaScript event that uses a $.getJason() call to a different controller/action method that works with (ASP) JsonResult. After I try this strategy I shall post my results for whomever is interested.

Answer 2

You want parseJSON not getJSON

http://api.jquery.com/jQuery.parseJSON/

Edit - Oh wait you are pointing your browser at the JsonResult as if it was an ActionResult ? That is not going to work.

Render a proper view, and use getJSON to call the JsonResult action.

Answer 3

getJSON is what you are looking for. Call that on the DOM ready event which will executes once the DOM finishes loading.

$(function(){
 //This code will be executed on the DOM ready ( when the page is loaded)

  $.getJSON("YourControllerName/MyMethod?userSelection=someValue",function(data){

      alert(data.FirstName);     
      alert(data.AnotherPropertyName);    

   });
});

getJSON is a shorthand of jQuery ajax method with datatype set as json

Assuming your JSON data you are retuning is something like this

{
    "FirstName": "Scott",
    "AnotherPropertyName": "SomeValue"
}

To return data like above, change your Action method like this

public JsonResult MyMethod(string userSelection)
{
  var result=new { FirstName="Scott", AnotherPropertyName="Great"};
  return Json(result,JsonRequestBehavior.AllowGet);
}