I have the following method.

[HttpPost]
public void DoStuff(string input) { ... }

The invocation by the following script reaches the method but the input parameter is null. I've tested all the below variations, with the same result each time.

$.post("/DoStuff", "{input=bbbd861b-62ae-4eb5-9677-3aa2e354c583}", function() {})
$.post("/DoStuff", "{input:bbbd861b-62ae-4eb5-9677-3aa2e354c583}", function() {})
$.post("/DoStuff", "{bbbd861b-62ae-4eb5-9677-3aa2e354c583}", function() {})
$.post("/DoStuff", "bbbd861b-62ae-4eb5-9677-3aa2e354c583", function() {})

There are no errors reported on this and similar approach used when I serialize a plex argument, does work.

Not sure how to trouble-shoot it.

I have the following method.

[HttpPost]
public void DoStuff(string input) { ... }

The invocation by the following script reaches the method but the input parameter is null. I've tested all the below variations, with the same result each time.

$.post("/DoStuff", "{input=bbbd861b-62ae-4eb5-9677-3aa2e354c583}", function() {})
$.post("/DoStuff", "{input:bbbd861b-62ae-4eb5-9677-3aa2e354c583}", function() {})
$.post("/DoStuff", "{bbbd861b-62ae-4eb5-9677-3aa2e354c583}", function() {})
$.post("/DoStuff", "bbbd861b-62ae-4eb5-9677-3aa2e354c583", function() {})

There are no errors reported on this and similar approach used when I serialize a plex argument, does work.

Not sure how to trouble-shoot it.

• javascript
• c#
• jquery
• ajax
• asp-mvc

Share Improve this question Follow edited Jan 10, 2016 at 16:50 Konrad Viltersten asked Jan 10, 2016 at 14:14 Konrad VilterstenKonrad Viltersten 39.5k8888 gold badges290290 silver badges510510 bronze badges 6

• Have you tried passing the name of the parameter as well? Something like $.post("/DoStuff", "guid=bbbd861b-62ae-4eb5-9677-3aa2e354c583", function() { ... });. See the jquery serialize docs – darth_phoenixx Commented Jan 10, 2016 at 14:32
• @phoenixx Yes. It hits the method but the variable is null, still... – Konrad Viltersten Commented Jan 10, 2016 at 14:52
• How about literally without any parentheses at all - input=bbbd861b-62ae-4eb5-9677-3aa2e354c583. I've created a sample project locally and this is what gets posted - not {input:yourinput} or {input=yourinput} but input=yourinput. I get the guid passed into the method successfully that way. – darth_phoenixx Commented Jan 10, 2016 at 16:46
• @phoenixx So, just to be perfectly clear, your call looks like this: $.post("/DoStuff", "input=bbbd861b-62ae-4eb5-9677-3aa2e354c583", function() {}), i.e. as a string, with the name of the parameter, equality sign and no brackets or colons? – Konrad Viltersten Commented Jan 10, 2016 at 16:52
• Precisely. I've called my parameter 'guid' but yes, it is exactly as follows: $.post("/DoStuff", "guid=bbbd861b-62ae-4eb5-9677-3aa2e354c583", function(response) { console.log(response); }. Also, I've taken a screenshot of my chrome network inspector so you can see what gets posted - see here imgur link. – darth_phoenixx Commented Jan 10, 2016 at 16:54

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4 Answers 4

Sorted by: Reset to default 2

I'd remend you to pass your key-value pair object as json:

var param = JSON.stringify({guid: 'bbbd861b-62ae-4eb5-9677-3aa2e354c583'});

$.post("/DoStuff", param, function() { ... }, 'json');

Note the last argument 'json'.

The property name must reflect the argument name (guid). If your argument name is id, your property name must be id. This is applicable for all types. MVC works in an case-insensitive way (at the very least for MVC4), which is cool by the way.

Doing so the framework will try to parse your argument to the type you declared.

I consider the guid as a valid one; the framework will not parse it properly if the value is not a valid guid. For the sake of testing, ensure that Guid.Parse("bbbd861b-62ae-4eb5-9677-3aa2e354c583") will return an object Guid.

If you declare DoStuff(string input) { }, pass a key-value pair as follows:

var param = JSON.stringify({input: 'bbbd861b-62ae-4eb5-9677-3aa2e354c583'});
$.post("/DoStuff", param, function() { ... }, 'json'); //json dataType

Inside DoStuff, you could parse it as Guid using Guid.Parse(input).

you can read the POST method with JQuery here.

You can easiest pass lot of variable like that :

$.post( "/DoStuff", {input : "bbbd861b-62ae-4eb5-9677-3aa2e354c583" })
 .done(function( data ) {
   alert( "Data Loaded: " + data );
});

if you have a function:

function doStuff(myVarStringGuid){
    $.post( "/DoStuff", {input: myVarStringGuid})
     .done(function( data ) {
       alert( "Data Loaded: " + data );
    });

}

On your PHP, you can get that variable like that :

$guid= $_POST['input'];    // bbbd861b-62ae-4eb5-9677-3aa2e354c583

If it's a C# you can get that variable like that:

string guid = Request.Form["input"];

Or with a Webmethod on codeBehind:

[WebMethod]
public static string DoStuff(string input)
{
    myInput = input;
}

But, the 500 error is when the server can be access to your page... If your route http://yourWebsite/DoStuff exist, it's probably because your object is nor serialized correctly.

Also, for send a form with JQuery, I use the plugin ajaxForm is very easy to send a form with Ajax with this: (and we gain lot of time^^ )

<form id="myForm" action="DoStuff" method="post"> 
    <input type="text" name="input" /> 
    <input type="submit" value="Submit Comment" /> 
</form>

<script>
    $('#myForm').ajaxForm(function() { 
        alert("Guid was received ;-)"); 
    }); 
</script>

Don't forgot you can use the browsers developer tools for check your AJAX requests...

Based on the ments from @phoenixx I 'll answer and add some extra value by an observation. The correct post URL is as follows. (Note: a single string, parameter name - equality sign - parameter value, no braces, no brackets, no parentheses.)

$.post("/DoStuff", "input=bbbd861b-62ae-4eb5-9677-3aa2e354c583", function() { });

It will issue the post if the method is in the right location in the directory structure and with the following signature.

[HttpPost]
public void DoStuff(string input) { ... }

---

I've seen you refer to a variable guid and I suspect that you're trying to pose the call in JavaScript using the attributes of a DOM element invoking the call. If so, please note that the following will not work.

var guid = event.target.attributes["id"];
// guid is: id="bbbd861b-62ae-4eb5-9677-3aa2e354c583"
// you need: "id=bbbd861b-62ae-4eb5-9677-3aa2e354c583"
$.post("/DoStuff", guid, function() { });

See the tiny difference? It's a tricky pitfall and easy to get confused. You want the serialized version of the attribute like this.

var guid = event.target.attributes["id"];
$.post("/DoStuff", "id=" + guid.value, function() { });

The error shows 500 Internal server error. So, somewhere your code at the server is failing because you may not have passed the values properly or the server code itself is buggy. When you do, form.serialize(), it produces a json structure of (key: value) pairs.

For example, "name": "Konrad" and at the server side you may accessed with

String name = request.getParameter("name");

But in other case, you are passing only value and not the key. So, the above statement could not find the parameter "name" in the request. This is what I can figure out from your question, may be you can debug your server side code for better clarity.

You need to send, {"guid": "WHATEVER_YOUR_VALUE"}

Its always better to use serialize() if you are working with form. But serialize() has some restrictions like it cannot serialize some fields from form based on the tag you used.