How to use jQuery to make a call to c# webservice to get return value

Question

I want to use jQuery to make a call to a c# web service called c.ashx which checks whether that username is valid and returns an error message as a string.

What should I put for data: and content type: if the return value of the c# webservice is a string value?

 jQuery.ajax({
 type: "GET",
 url: "/services/CheckUserName.ashx",
 data: "",
 contenttype: "",

 success: function (msg) {
     alert("success");

 },
 error: function (msg, text) {
     alert(text);
 }
 });

I have created a .asmx file instead, but it doesn't get called by the jQuery. Is the following correct?

jQuery.validator.addMethod("UsernameCheck", function (value, element) {
    jQuery.ajax({
        type: "POST",
        url: "/services/CheckUsername.asmx?CheckUsername",
        data: '{ "context": "' + jQuery("#username").value + '"}',
        contentType: 'application/json; charset=utf-8',
        dataType: 'json',

        success: function (msg) {
            alert("success");

        },
        error: function (msg, text) {
            alert(text);
        }
    });
});

Jeff Schumacher · Accepted Answer · 2010-05-24 15:42:49Z

5

Data should contain the parameters of the method you are calling in a web service. However, the ashx extension is for an HTTP Handler, which is not a good choice for this scenario. A web service should by used instead.

So if you were calling /services/LoginServices.asmx?CheckUserName, and CheckUserName.asmx had a webmethod ValidateUser such as

public string ValidateUser(string username)

then the data attribute for jQuery would be

data: '{ "username": "' + usernameValue + '"}'

your contentType should be application/json; charset=utf-8, and dataType should be "json".

Note that you're not going to call /services/CheckUserName.asmx, the name of the method in the web service has to be appended to the webservice url, /services/LoginServices.asmx?CheckUserName.

Also, you'll need to change your type to "POST".

Here's a complete example:

$.ajax({
type: 'POST',
url: 'LoginServices.asmx/CheckUserName',
data: '{"username": "' + usernameValue + '"}',
contentType: 'application/json; charset=utf-8',
dataType: 'json',
success: function(msg) {
    alert("Result: " + msg);
},
error: function(XMLHttpRequest, textStatus, errorThrown) {
    alert("Error: " + textStatus);
}});

Hope this helps

answered May 24, 2010 at 15:42

Jeff Schumacher

3,1563 gold badges24 silver badges23 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Theomax Over a year ago

Thanks for your reply :) The c# method is only called when I comment out the data: line and it errors because the username entered by the user isn't being passed to the c# method. The method in the c# file is public void ProcessRequest(HttpContext context) { } and it gets the username using string _username = context.Request["username"]; - should I change this method to public string ValidateUser(string username)? or can we pass the username a different way? Thanks,

Jeff Schumacher Over a year ago

Sounds like you're using an HTTP Handler instead of a Web Service, any specific reason for this? It's possible to use a handler, it's just not a common practice, and the implementation will be different. My answer was based on using a web service instead of a handler. Sorry for the confusion.

Theomax Over a year ago

HTTP handler is already there - could you provide an example using this code? I created a .asmx webservice but it doesn't get called.

Theomax · Accepted Answer · 2010-05-26 08:05:54Z

0

The jQuery code wasn't working because it wasn't calling the webservice. I fixed this by creating a HTTP handler class and passing it the username. I changed the value for data: to the following and it passed the username entered by the user:

data: "username=" + jQuery("#username").val(),

answered May 26, 2010 at 8:05

Theomax

6,82815 gold badges56 silver badges73 bronze badges

Collectives™ on Stack Overflow

How to use jQuery to make a call to c# webservice to get return value

2 Answers 2

3 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related