Question

I am trying to return a json string via jQuery of an object using the following function. The problem I do not seem to be able to overcome is my json result comes out the other end wrapped in double quotes.

I have seen in this post that I should;

have your method return an actual object and let the JSON serialization of the framework do the heavy lifting for you

But I don’t fully understand that this means.

This is the function I am using.

Public Function getLine() As String

    Dim data As List(Of ArrayList) = New List(Of ArrayList)

    For Each q In getAllData()
        Dim a As New ArrayList
        Dim d As Date = q.DateTime
        a.Add(d.Ticks)
        a.Add(q.TotalRevenue)
        data.Add(a)
    Next

    Dim s As New Serie
    s.data = data
    Dim str As String = JsonConvert.SerializeObject(s)
    Return str

End Function

Any ideas greatly appreciated.

$.ajax({
    type: "POST",
    dataType: "json",
    data: "{}",
    contentType: "application/json; charset=utf-8",
    url: "_services/ScriptService.asmx/getData",
    success: function (items) {
        var data = eval("(" + items.d + ")");
    },
    cache: false,
    error: function (XMLHttpRequest, textStatus, errorThrown) { alert(errorThrown); }
});

‘items.d’ contains…

"{"data":[[634420512000000000,100000.0000] ... [634421376000000000,100086.0000]]}"

if i eval ‘items.d’ i get…

[[634420512000000000, 100000] ... [634421376000000000, 100086]

I read somewhere that eval is evil, is this true?

Answer 1

Not clear whether you’re having problem with the code you posted or with the javascript that handles it. So you’re getting a result, it’s just wrapped in double quotes? If you put a breakpoint at the beginning of the javascript callback function in Visual Studio, you should be able to see what is being returned. Just call eval on that string, and extract out whatever you need from the object. From that other article you quoted:

You obviously just want to get at the
object. You have 2 options: –

1) use eval in your javascript to turn
the string into an object e.g.

function onSuccessCallback(retval) {
var obj = eval(retval.d); } //put the breakpoint here and use the immediate or watch window to see what the value for retval.d is. Post it to your question so we can see what you’re getting.