knockout javascript object issue - asp.net

Question

I am stuck at the approach for binding javascript objects to knockout observable arrays.I am using asp.net .I am lost at assigning the response data from ajax call to the javascript object.
My aspx page
<table id="gvActivityForm" class="test">
<th class="thdata">
TestSample
</th>
<tbody data-bind="foreach: arraytoadd">
<tr>
<td data-bind="text: testid"></td>
</tr>
</tbody>
</table>
<script type="text/javascript">
var TemplateFunction = function()
{
var self = this;
self.testid= ko.observable(0);
} //end
RealFunction = function ()
{
var self = this;
self.arraytoadd = ko.observableArray([]); //Adding an array
self.addevent = function()
{
self.arraytoadd.push(new TemplateFunction());
}
} //end of javascript object
objRealFunction = new realFunction();
ko.applyBindings(objRealFunction);
I am getting the data through ajax call .
$.ajax({ //start ajax call for posting and getting the data back
type: 'POST',
url: 'PopupWebService.asmx/ReceiveandSendJobActivity',
data: JSON.stringify({item:obj}),
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (response) {
for(var i=0;i<response.d.length;i++)
{
TemplateFunction.testid= response.d[i].TestId; //My question is how do I assign the data .I am lost here
}
script>

Answer 1

You haven't instantiated any instances of your 'TemplateFunction'
When your data comes back from your ajax call - do something like this using your objRealFunction object:
success: function (response) {
for(var i=0;i<response.d.length;i++)
{
var templateFunction = new templateFunction();
templateFunction.testId(response.d[i].testId);
objRealFunction.arraytoadd.push(templateFunction)
}
}
You'll also need to update your view as at the moment it's expecting a property called testId on each member of the observableArray.
You will need to change your html binding to
foreach: arrayToAdd().templateFunction
as you have defined your testId property as a ko.observable() on the templateFunction object

Answer 2

knockout observables are treated as functions so in order for you to set the value of an observable you cannot user regular assignment operator syntax but rather pass the new value as a parameter to the knockout observable function:
TemplateFunction.testid(response.d[i].TestId);