Null Reference exception when calling ViewData in javascript

Question

_{Tuesday, November 15, 2011 9:13 AM}

I am trying to access controller ViewData["done"] in javascript my code is

var str = <%= (Boolean)ViewData["done"] ? "true" : "false" %>;

but this always gives me error Null Reference exception, Can any one tell me what is the problem.

Thanks 

All replies (10)

_{Wednesday, November 16, 2011 9:58 AM ✅Answered}

Thanks guys i got the solution, What i did is i made a async= true Ajax call and return the TempData value in javascript and get it done.

_{Tuesday, November 15, 2011 9:19 AM}

REfer the link

http://stackoverflow.com/questions/5863094/asp-net-mvc-using-viewdata-in-javascript

http://stackoverflow.com/questions/5528815/problem-in-acessing-viewdata-in-javascript

_{Tuesday, November 15, 2011 9:29 AM}

I tried all of there but still error is coming.

_{Tuesday, November 15, 2011 9:30 AM}

Can you try with tempdata instead of view data?

_{Tuesday, November 15, 2011 10:03 AM}

Same error i think i need to handle null reference but i do not know how i will do that in javascript.

_{Tuesday, November 15, 2011 11:31 AM}

the null reference is in the server view code, not javascript. try:

var str = <%= ((bool?)ViewData["done"]?? false) ? "true" : "false" %>;

_{Tuesday, November 15, 2011 11:55 AM}

now object reference error not coming, since i am assigning variable on save complete in controller and code is executing but seems value not setting and in javascript its always showing false.

my code is

    function Grid_OnComplete(e) {
 
        if (e.name == "submitChanges") {
            var str = <%= ((bool?)ViewData["done"]?? false) ? "true" : "false" %>;  
            alert(str);                
            if (str == true) {
                alert("Saved");
            }
        }
    }

_{Tuesday, November 15, 2011 1:32 PM}

thats because there is no value in ViewData["done"], thats the case the modified code handles. you need to set a ViewData["done"] = true (or ViewBag.done = true) in the controller before the view is called.

_{Tuesday, November 15, 2011 3:00 PM}

bruce i set this value ViewData["done"] = true but view is already loaded and when my update is completed then i am setting this

ViewData["done"] = true

_{Tuesday, November 15, 2011 7:33 PM}

this is no valid reason to update ViewData after your controller calls return View(). its a coding error. please explain what you are doing.