asp.net mvc 4 - Radio button not showing as checked -

i'm using knockout mvc 4. cshtml is:

... <span>@html.radiobuttonfor(m => m.isactive, true, new { @class = "statusradiobutton", data_bind = "checked: isactive" })</span> <span>@html.radiobuttonfor(m => m.isactive, false, new { @class = "statusradiobutton", data_bind = "checked: isactive" })</span> ... 

my ko:

... self.isactive = ko.observable(product.isactive); ... 

it updates database correctly, doesn't show radio button checked when page loaded. tried using checked = "checked" html attribute , doesn't work either. advice?

is product.isactive observable? if need execute observable product.isactive()

by initialising self.isactive = ko.observable(product.isactive()); going set once.

try turning observable like:

self.isactive = ko.computed(function() {                                 return product.isactive();                              }); 

edit: try changing radio buttons this:

<span>@html.radiobuttonfor(m => m.isactive, true, new { @class = "statusradiobutton", data_bind = "checked: isactive", value="true" })</span> <span>@html.radiobuttonfor(m => m.isactive, false, new { @class = "statusradiobutton", data_bind = "checked: isactive", value="false" })</span> 

and writing observable use boolean value in isactive string.

self.isactive = ko.computed(function() {                                 return product.isactive.tostring();                              });