ASP.NET ajax c# always returns undefined

Question

I searched and tried for days now but I cant find any solution. I looked up nearly every tutorial and nearly every question on this board, but no code worked for me. (I know this is a duplicate question but since no other code worked at all, you are my last hope)

I'm trying to return a AJAX request from C# in ASP but no matter what it always returns undefinded even with code from tutorials.

Here is what I have in my Default.aspx

<script type="text/javascript">
    $(document).ready(function () {

     $.ajax({
         type: "POST",
         url: "Default.aspx/GetData",
         contentType: "application/json; charset=utf-8",
         dataType: "json",
         success: function (response) {
             alert(response.d);
         },
         failure: function (response) {
             alert(response.d);
         }
     });
 });
</script>

and here is my codebehind from Default.aspx.cs

[WebMethod]
public static string GetData()
{
    return "This string is from Code behind";
}

The Problem is: the c# method dont activate... I dont know why and I get no errormessage.

Can you pls help me? Thanks for your advice

return JSON data instead of string, your setting dataType to json ,ajax expecting json — Saravanan N
– Saravanan N, Commented Jun 1, 2016 at 5:58
Use alert(response); instead, because your response object doesn't have a property of d. — Afzaal Ahmad Zeeshan
– Afzaal Ahmad Zeeshan, Commented Jun 1, 2016 at 7:00

KhawajaAtteeq · Accepted Answer · 2016-06-01 06:58:44Z

3

I just copy pasted your code and it worked Like a charm as one can see in the following links

http://prntscr.com/baw6qb

I don't see what are you doing wrong, Please place a debugger in you JAVASCRIPT and see if its been called or Not. Rest is working fine in my Environment. There is no mismatch of text or no json instead of string needed. Please check you code thoroughly. you must be missing something some where
Output screenshot enter link description here

Update

edited Jun 1, 2016 at 6:58

answered Jun 1, 2016 at 6:15

KhawajaAtteeq

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10 Comments

Robin Schambach Over a year ago

your links are blocked by my companies filter^^" I cant see your screenshot or code My Javascript is called and workes, but my c# code dont run. No matter what I code in my c# function it does not run. Is there any trick or hidden hint that I have to do in Visual studio?

KhawajaAtteeq Over a year ago

as I said my dear friend I just copy past your code and it worked as you can't see the picture, let me tell you I'd a debugger placed their, and it was working. if its not calling your method in any case. can you use firebug to see if the request was even sent.Net option of the firebug shows you all the methods that execute from your page. please check that once

Robin Schambach Over a year ago

Firebug Message from Default.aspx/GetData: {"Message":"Authentication failed.","StackTrace":null,"ExceptionType":"System.InvalidOperationException" }

KhawajaAtteeq Over a year ago

Now that is your actual error Authentication failed

KhawajaAtteeq Over a year ago

This means User authentication hasn't been provided or It failed some how`

|

Community · Accepted Answer · 2017-05-23 10:31:12Z

1

I had the exact same problem and it was driving me crazy. Finally, after hours of doing this and that, I checked the JSON response and it was like this : {"Message":"Authentication failed.", "StackTrace":null, "ExceptionType":"System.InvalidOperationException"}

And I searched for this issue and FINALLY found an answer over here! Hope this helps you too! :)

edited May 23, 2017 at 10:31

CommunityBot

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answered Jun 19, 2016 at 7:25

Prabash Darshana

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Comments

Arun Prasad E S · Accepted Answer · 2022-07-13 04:13:03Z

1

Build format like this

{
    "employees":[
                  {"firstName":"John", "lastName":"Doe"},
                  {"firstName":"Anna", "lastName":"Smith"},
                  {"firstName":"Peter", "lastName":"Jones"}
    ]
}

and access through in jquery like employees[0].firstname

edited Jul 13, 2022 at 4:13

answered Jun 1, 2016 at 6:04

Arun Prasad E S

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1 Comment

Robin Schambach Over a year ago

where do i have to put this? I dont really know what I should do with your code

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