How to return value to AJAX from code behind?

Question

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How To Return Value From Code Behind To AJAX?

This is my AJAX code

$.ajax({
        type: 'POST',
        url: 'country_management.aspx/save',
        cache: false,
        data: "{'parameter':'paramValue'}",
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: function (data) {
                 alert(data.d);
                 if (data.d == "error") {
                    $('.success_box').hide();
                    $('.error_box').show();
                 }
                 else {
                    $('#name').val('');
                    $('.error_box').hide();
                    $('.success_box').show();
                 }
        }
});

Code Behind:

[WebMethod]
[ScriptMethod]
public static string save(string parameter)
{
    string name = HttpContext.Current.Request.QueryString["name"].Trim();
    return "error";
}

after writing the first line, return statement does not return anything to the AJAX.

You're not returning JSON, but a plain string. Check this out http://stackoverflow.com/questions/5364343/asp-net-web-forms-json-return-result. — Alex, Sep 14 '12 at 08:40
are you saying it errors out after this line? string name = HttpContext.Current.Request.QueryString["name"].Trim(); — Rohan Büchner, Sep 14 '12 at 08:41
Did you -really- just create duplicate account for this purpose? — J. Steen, Sep 14 '12 at 08:43
@Rohan I have returned "error" just to check if it is Returned or not. If I don't write first line, return statement does return... — Chirag Gohel, Sep 14 '12 at 08:45
then id check what @Rawling said, confirm that QueryString["name"] actually exists. — Rohan Büchner, Sep 14 '12 at 08:47
@Rohan Thanks. Actually my QueryString["name"] is null. Let me know, How to pass parameters then?? — Chirag Gohel, Sep 14 '12 at 08:54
The marked duplicate question now returns an error as the question is gone. Does this mean this is no longer a dupliate? — Phil3992, Sep 04 '17 at 15:04

score 0 · Answer 1 · answered Sep 14 '12 at 08:44

Because you didn't post any field or property "name" If you do the ajax after clicked in a button inside form, data will be the form serialized.

Another thing is, why should you expect "name" var in query string, I don't see any url with aspx?name="any name"

Rohan Büchner · Accepted Answer · 2012-09-14T09:58:30.913

Without knowing the context of the whole application is kind of difficult to answer your question. (Does name get supplied from elsewhere in the app, you could make use of a session?)

But what is stopping you from passing the name through in the ajax call? Rather than just sending through'parameter':'paramValue'.

You have to remember your query string is supposed to contain the parameter you're looking for. at the moment it's looking something like.

http://www.somesite.com/country_management.aspx/save?parameter=paramValue

when you actually need

e.g.

http://www.somesite.com/country_management.aspx/save?parameter=paramValue&name=newName

Javascript

$.ajax({
        type: 'POST',
        url: 'country_management.aspx/save',
        data: { parameter:'paramValue', name: 'newName'},
        success: function (data) { 
           //do something with the response
        }         

});

Codebehind

[WebMethod]
[ScriptMethod]
public static string save(string parameter, string name)
{
    PerformSave(name, parameter);
    return "Data Saved!";
}

TIP

Try out this app. Fiddler. It's extremely useful when you're working with things like ajax calls etc. Actually any web development. :)

How to return value to AJAX from code behind?

2 Answers2