HTML and CSS Reference
In-Depth Information
function OnSuccess(results) {
alert("Converted Temperature : " + results.Value + " " + results.Unit);
function OnError(err) {
alert(err.status + " - " + err.statusText);
The Convert button's click event handler contains the jQuery code for invoking the Convert()
method. The $.ajax() function has many configurable settings. Some common ones are used in Listing
2-14. The url setting allows you to specify the remote resource URL. For a WCF service, the URL takes the
form <path_to_svc_ile>/<method_name> .
The type option lets you specify the HTTP request type to be used while making the request. The
Convert() method is configured with the [WebInvoke] attribute to use a POST method, and hence type is
POST . The data setting indicates the data to be sent to the server (if any) while making the call. Notice how
data is captured in JSON format. A JSON object takes the form of key-value pairs: a key and its value are
separated by a colon ( : ), and multiple key-value pairs are delimited by a comma ( , ).
The dataType setting governs the data type of the response (XML, JSON, and so on). Recollect that the
[WebMethod] attribute specified ResponseFormat as JSON, so dataType here must be set to JSON to correctly
process the data coming from the server.
If Convert() returns successfully, the function specified by the success option ( OnSuccess ) is called. If
there is any error while calling the WCF service, a function specified by the error option ( OnError ) is called.
The OnSuccess() function is where you process the data returned from the WCF service. OnSuccess()
receives the return value of Convert() (the TemperatureData object) as a parameter. You can access its Value
and Unit properties and display an alert box to the user.
In the OnError() function, you typically flag the error to the user or take some corrective action.
OnError() receives an error object; you can display its status and statusText properties to the user.
Figure 2-10 shows a sample run of the Web Forms application.
Figure 2-10. Sample run of Web Forms application that converts temperatures
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