Calling a WCF Data Service From jQuery

July 4, 2010

Calling a WCF Data Service From jQuery


I’m working on a lecture Calling a WCF Data Service from jQuery
about OData which I’ll
will present next month
(stay tuned for more
details in the near future).
One of the things that
I want to show is how easy
and simple it is to consume a WCF Data Service (OData feed)
with the jQuery library. In the post I’ll show you exactly how
to do that.


jQuery’s getJSON Method


When you want to load JSON data from the server using a GET HTTP
request in jQuery you will probably use the getJSON method. That
method gets as input the server URL, a map of key-value pairs which
holds parameters to the server and a callback function to use when
the response arrives back to the client and returns the server response
in JSON format.
This method is the best candidate for consuming WCF Data Services
endpoints. If I want to use the getJSON method I’ll do something
like the example provided in the getJSON documentation:



$.getJSON(‘ajax/test.json’, function(data) {
  $(‘.result’).html(‘<p>’ + data.foo + ‘</p>’
    + ‘<p>’ + data.baz[1] + ‘</p>’);
});

How to Consume WCF Data Service with jQuery getJSON Method


When we understand that WCF Data Service is just an HTTP
endpoint which returns JSON answer if addressed with
JSON request the road is very clear. If I want to consume the
service all I need to do is to create the relevant URI with the
WCF Data Service URI conventions and that is it.
The following code is an example for that:



$.getJSON(“/Services/SchoolService.svc/Courses”, null,
    function (data) {
        var sb = new Sys.StringBuilder();
        sb.append(“<div>”);                                
        $.each(data.d, function (i, item) {
            CreateDivForOneCourse(sb, item)
        });
        sb.append(“</div>”);
        $(‘#divResults’).html(sb.toString());
    });

What this code is doing is going to a WCF Data Service endpoint 
that is called SchoolService.svc and retrieve the courses entity set
it holds. I don’t pass any parameters to the request so the key-value
pair is null. In the callback function I create a StringBuilder object and
append to it the response by iterating the data and creating a div
for every course. In the end I put the result as html in a div which has
an id of divResults.


The All Example Page



<%@ Page Language=“C#” AutoEventWireup=“true” CodeBehind=“ConsumeDataServicejQuery.aspx.cs”
    Inherits=“DataServiceAjaxClient.ConsumeDataService.ConsumeDataServicejQuery” %>
 
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”>
<html xmlns=“http://www.w3.org/1999/xhtml”>
<head runat=“server”>
    <title></title>
    <script src=“../Content/Scripts/jquery-1.4.1.js” type=“text/javascript”></script>
    <script src=“../Content/Scripts/jquery-1.4.1-vsdoc.js” type=“text/javascript”></script>
    <script type=“text/javascript”>                
        var ajaxRequest;
 
        $(document).ready(function () {                        
            $(‘#btnShowCourses’).click(function () {
                GetCoursesData();
            });
        });
 
        function GetCoursesData() {
            if (ajaxRequest != null) {
                ajaxRequest.abort();
            }
            ajaxRequest = $.getJSON(“/Services/SchoolService.svc/Courses”, null,
            function (data) {
                var sb = new Sys.StringBuilder();
                sb.append(“<div>”);                                
                $.each(data.d, function (i, item) {
                    CreateDivForOneCourse(sb, item)
                });
                sb.append(“</div>”);
                $(‘#divResults’).html(sb.toString());
            });
        }
 
        function CreateDivForOneCourse(stringBuilder, item) {
            stringBuilder.append(“<div><span>”);
            stringBuilder.append(item.CourseID);
            stringBuilder.append(“</span>&nbsp;<span>”);
            stringBuilder.append(item.Title);
            stringBuilder.append(“</span></div>”);
        }              
    </script>
</head>
<body>
    <form id=“form1″ runat=“server”>
    <div>
        <asp:ScriptManager ID=“ScriptManager1″ runat=“server”>
        </asp:ScriptManager>
        <input type=“button” id=“btnShowCourses” value=“Show Courses” /><br />
        <div id=“divResults” />
    </div>
    </form>
</body>
</html>

After running this example the result looks like:
getJSON result


Summary


Consuming WCF Data Services with jQuery is very easy task.
By using the getJSON method we create the HTTP GET request
to the service and get the returning data in JSON format to
our disposal. 

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2 comments

  1. sergeJuly 10, 2010 ב 22:11

    Great post. However there is a small bug in the code.

    $.each(data.d, function (i, item)

    should be
    $.each(data.d.results, function (i, item)

    Reply
  2. Gil FinkJuly 11, 2010 ב 7:56

    @serge,
    Thanks for the comment but I’m only publishing working code and the published code is working at my enviroment.

    Reply