using viewbag with jquery - asp.net mvc 3

Question

I have a ViewBag.IsLocal set to true in controller. I would like to use jquery to check the ViewBag value and display an alert.

Code:

if(@ViewBag.IsL         


        

Answer 1

Assuming you have set the IsLocal property to a boolean value in your controller action:

public ActionResult Index()
{
    ViewBag.IsLocal = true;
    return View();
}

you could do this on the view:

<script type="text/javascript">
    @if(ViewBag.IsLocal)
    {
        <text>alert("yeah");</text>
    }
</script>

And please don't use ViewBag/ViewData. Use view models and strongly typed views.

So here's a better approach that I prefer. You could JSON serialize your view model into a javascript variable and then deal with it. Like this:

@model MyViewModel

<script type="text/javascript">
    var model = @Html.Raw(Json.Encode(Model));
    // at this stage model is a javascript variable containing
    // your server side view model so you could manipulate it as you wish
    if(model.IsLocal)
    {
        alert("hello " + model.FirstName);
    }
</script>

Obviously if you don't need your entire view model you could JSON serialize only a subset of it => only the part that will be needed by client scripts.

Answer 2

You can use the following function

function parseBoolean(str)
{ 
   return /^true$/i.test(str);
}

and Use it as

if(parseBoolean('@ViewBag.IsLocal') == true) 
{ 
   alert("yeah");
}

Answer 3

If you view source on the rendered page, what's being inserted in place of your razor nugget? If IsLocal is a bool type, I think you'll see this:

@if(True == true)
{
  alert("yeah");
}

The reason for that is because true.ToString() is True.

In which case, you'll need to make a string comparison there:

if('@ViewBag.IsLocal' == 'True')
{
  alert("yeah");
}