Questions about knockout - asp.net

Question

1.i have 2 question about knockout on asp.net.
server side method:
<WebMethod>
Public Shared Function foo() As List(Of person)
Return New List(Of person)() From {New person With {.id = 1, .fname = "meysam"},
New person With {.id = 2, .fname = "yasaman"}}.ToList
End Function
json and binding to knockout:
var VM = {};
$.getJSON("default.aspx/foo", function (data) {
var tmp = JSON.stringify(data.d);
VM.model =
ko.applyBindings(VM);
});
html:
<div data-bind="foreach: model">
<h3 data-bind="text: id">
</h3>
<p>
Name: <span data-bind="text: fname"></span>
</p>
but when i run in browser.No nothing will happen.fname,id Will be displayed.
2.what The difference between $.getJSONand dataType:json?
$.getJSON("default.aspx/foo", function (data) {
var tmp = JSON.stringify(data.d);
});
and
$.ajax({
type:"post",
url:"default.aspx/foo",
contentType:"application/json;charset=utf-8",
dataType:"json",
success:function(data){}
})

Answer 1

So, this really should be two actual questions, but anywho (in reverse order!):
2: From the jQuery documentation: $.getJSON is a shorthand Ajax function, which is equivalent to:
$.ajax({
url: url,
dataType: 'json',
data: data,
success: callback
});
So they are the same.
1: Your attempt to call JSON.stringify() on the result of a getJSON call is redundant. getJSON already does that. The problem is two-fold: neither of those parsers can parse .net lists (I might be wrong about this, but I am 60% sure). In either case, the better solution would be to serialize the list into JSON in the web method, and return already parsed JSON. .NET has this ability built-in.
Two, your list doesn't have a d property. So even when you sort that part out, you are going to get an undefined error.

Answer 2

About your knockout question:
Here's code to solve your issue:
Output
ASPX code behind
[WebMethod]
public static IEnumerable<KnoPerson> GetPeople()
{
return Builder<KnoPerson>.CreateListOfSize(10).Build();
}
public class KnoPerson
{
public int ID { get; set; }
public int FirstName { get; set; }
}
ASPX
<script type="text/javascript" src="Scripts/jquery-1.7.2.min.js"></script>
<script type="text/javascript" src="Scripts/knockout-2.1.0.js"></script>
<script type="text/javascript" src="Scripts/knockout.mapping-latest.js"></script>
<script type="text/javascript">
$(function () {
var model = {};
$.ajax({
url: "KnockoutBindingFromPageMethod.aspx/GetPeople",
data: null,
type: "POST",
dataType: "json",
contentType: "application/json",
cache: false,
async: false,
success: function (myData) {
model.people = ko.mapping.fromJS(myData.d);
model.yo = ko.observable("plop");
ko.applyBindings(model);
},
error: function (xhr) {
alert(xhr.responseText);
}
});
});
</script>
<div data-bind="text: yo"></div>
<div data-bind="foreach: people">
<h3 data-bind="text: ID"></h3>
<p>
Name: <span data-bind="text: FirstName"></span>
</p>
</div>
2.what The difference between $.getJSONand dataType:json?
.getJSON is a shortcut, and it internally uses .ajax
The .getJSON function sets the following properties:
dataType: “json”
type: "GET"