Using AJAX call in MVC5

Question

I have tried to use AJAX call in an MVC5 project as many similar examples on the web, but every time there is an error i.e. antiforgerytoken, 500, etc. I am looking at a proper AJAX call method with Controller Action method that has all the necessary properties and sending model data from View to Controller Action. Here are the methods I used:

View:

@using (Html.BeginForm("Insert", "Account", FormMethod.Post, new { id = "frmRegister" })) 
{
    @Html.AntiForgeryToken()
    //code omitted for brevity
}



<script>

    AddAntiForgeryToken = function (data) {
    data.__RequestVerificationToken = $('#__AjaxAntiForgeryForm input[name=__RequestVerificationToken]').val();
    return data;
    };

$('form').submit(function (event) {
        event.preventDefault();

        //var formdata = JSON.stringify(@Model); //NOT WORKING???
        var formdata = new FormData($('#frmRegister').get(0));
        //var token = $('[name=__RequestVerificationToken]').val(); //I also tried to use this instead of "AddAntiForgeryToken" method but I encounter another error

        $.ajax({
            type: "POST",
            url: "/Account/Insert",
            data: AddAntiForgeryToken({ model: formdata }),
            //data: { data: formdata, __RequestVerificationToken: token },
            //contentType: "application/json",
            processData: false,
            contentType: false,

            datatype: "json",
            success: function (data) {
                $('#result').html(data);
            }
        });

    });
</script>

Controller: Code cannot hit to this Action method due to antiforgerytoken or similar problem.

[HttpPost]
[AllowAnonymous]
[ValidateAntiForgeryToken]
public JsonResult Insert(RegisterViewModel model)
{
    try
    {
         //...
         //code omitted for brevity
    }
}

I just need a proper AJAX and Action methods that can be used for CRUD operations in MVC5. Any help would be appreciated.

UPDATE: Here is some points about which I need to be clarified:

1) We did not use "__RequestVerificationToken" and I am not sure if we send it to the Controller properly (it seems to be as cookie in the Request Headers of Firebug, but I am not sure if it is OK or not). Any idea?

2) Should I use var formdata = new FormData($('#frmRegister').get(0)); when I upload files?

3) Why do I have to avoid using processData and contentType in this scenario?

4) Is the Controller method and error part of the AJAX method are OK? Or is there any missing or extra part there?

Answer 1

If the model in your view is RegisterViewModel and you have generated the form controls correctly using the strongly typed HtmlHelper methods, then using either new FormData($('#frmRegister').get(0)) or $('#frmRegister').serialize() will correctly send the values of all form controls within the <form> tags, including the token, and it is not necessary to add the token again.

If your form does not include a file input, then the code should be

$('form').submit(function (event) {
    event.preventDefault();
    var formData = $('#frmRegister').serialize();
    $.ajax({
        type: "POST",
        url: '@Url.Action("Insert", "Account")', // do not hard code your url's
        data: formData,
        datatype: "json", // refer notes below
        success: function (data) {
            $('#result').html(data);
        }
    });
});

or more simply

$.post('@Url.Action("Insert", "Account")', $('#frmRegister').serialize(), function(data) {
    $('#result').html(data);
});

If you are uploading files, then you need you need to use FormData and the code needs to be (refer also this answer and

$('form').submit(function (event) {
    event.preventDefault();
    var formData = new FormData($('#frmRegister').get(0));
    $.ajax({
        type: "POST",
        url: '@Url.Action("Insert", "Account")',
        data: formData,
        processData: false,
        contentType: false,
        datatype: "json",  // refer notes below
        success: function (data) {
            $('#result').html(data);
        }
    });
});

Note that you must set both processData and contentType to false when using jQuery with FormData.

If you getting a 500(Internal Server Error), it almost always means that your controller method is throwing an exception. In your case, I suspect this is because your method is returning a partial view (as suggested by the $('#result').html(data); line of code in you success callback) but you have specified that the return type should be json (your use of the datatype: "json", option). Note that it is not necessary to specify the dataType option (the .ajax() method will work it out if its not specified)

If that is not the cause of the 500(Internal Server Error), then you need to debug your code to determine what is causing the expection. You can use your browser developer tools to assist that process. Open the Network tab, run the function, (the name of the function will be highlighted), click on it, and then inspect the Response. It will include the details of the expection that was thrown.

Answer 2

contentType should be application/x-www-form-urlencoded

Try this code

    <script>
$('form').submit(function (event) {
        event.preventDefault();

    $.ajax({
        method: "POST",
        url: "/Account/Insert",
        data: $(this).serialize(),
       contentType:"application/x-www-form-urlencoded",
        success: function (data) {
       $('#result').html(data);
        },
        error: function (jqXHR, textStatus, errorThrown) {
            console.log(errorThrown);
        }
    });
});
    </script>