"Invalid JSON Primitive" in Ajax Processing

Invalid JSON primitive in Ajax processing

Just a guess what does the variable json contain after

var json = Sys.Serialization.JavaScriptSerializer.serialize(obj);?

If it is a valid json object like {"foo":"foovalue", "bar":"barvalue"} then jQuery might not send it as json data but instead serialize it to foor=foovalue&bar=barvalue thus you get the error "Invalid JSON primitive: foo"

Try instead setting the data as string

$.ajax({
    ...
    data: '{"foo":"foovalue", "bar":"barvalue"}', //note the additional quotation marks
    ...
})

This way jQuery should leave the data alone and send the string as is to the server which should allow ASP.NET to parse the json server side.

How to solve Invalid JSON Primitive error on Ajax?

Your postData is invalid JSON, a string needs quotes around it:

'{fileName:'+name+'}'

It should be:

 '{fileName:"'+name+'"}'

Invalid JSON primitive On Post

When your specify contentType: "application/json, you must stringify the data you send as JSON. In your case, the data is a javascript objec` (which contains some stringified data), not JSON.

Since userdetails is already stringified (using JSON.stringify()), then change the ajax code to

$.ajax({
    url: url,
    type: 'POST',
    contentType: 'application/json; charset=utf-8',
    dataType: 'json',
    data: userdetails,
    success: function (data) {
        ...
});

However, there is no need to send it as JSON. You can use the default 'application/x-www-form-urlencoded; charset=UTF-8'

Delete the userdetails = JSON.stringify(userdetails); line of code, and then its just

$.ajax({
    url: url,
    type: 'POST',
    dataType: 'json',
    data: userdetails,
    success: function (data) {
        ...
});

Note in both cases, you can omit the traditional: false option.

And if you have generated your form controls correctly using the HtmlHelper methods to bind to your model properties, then you do not need to manually create the object. You can simply use .serialize(). In addition, you should be handling the forms submit event, not the button click event, and checking .valid()

$('form').submit(function(e) {
    e.preventDefault();
    if (!$(this).valid()) {
        return;
    }
    var userdetails = $(this).serialize();
    var url = '@Url.Action("WFUserEdited", "WFUser")';
    $.ajax({
        url: url,
        type: 'POST',
        dataType: 'json',
        data: userdetails,
        success: function (data) {
            ...
    });
});

Invalid JSON primitive ERROR

You are promising a content type of application/json but are sending a plain JS Object, which gets serialised as percentile-encoded-string by jQuery. This serialization might be far from valid JSON.

Change:

data: {'partyId':party,'PartySelCombo':valueFrom,'DocumentId':DocId},

to:

data: JSON.stringify({'partyId':party,'PartySelCombo':valueFrom,'DocumentId':DocId}),

Getting Invalid JSON primitive error from MVC AJAX call

You posting back an object, not json, so you need to remove the contentType: 'application/json;', ajax option so that it uses the default (which is 'application/x-www-form-urlencoded; charset=UTF-8') Alternatively you need to use JSON.stringify() to convert the object to a JSON string.

Side note: It is not necessary to quote the property names. It can be

var dataObject = {
    FirstName: $('#FirstName').val(),
    ....

Invalid JSON primitive when sending POST request

Your issue is because you're not sending valid JSON. You need to wrap the keys in double quotes. Also, subscriptionJson is a literal string in your code. You need it to be a string variable.

data: '{"subscriptions": ' + subscriptionJson + '}',

Or, even better, just provide a plain object to jQuery and let it encode the values for you:

data: { subscriptions: subscriptionJson },

Jquery Ajax POST to C# WebMethod Errors with Invalid JSON primitive: System.Object.

public static string SubData(Selection item)
{
    var serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
    //ERROR OCCURS HERE
    var selection = serializer.Deserialize(item.ToString());
    return "this is successful";
}

Here, item is not a string (and thus not the JSON being sent). Since you're calling ToString() on it, it's likely the library is trying to deserialize text similar to System.Object - which will fail.

At a quick glance at the code, it looks like item is already deserialized for you, so you don't need to do anything further

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