Jquery – How to trigger the “error” callback in a jQuery AJAX call using ASP.NET MVC

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This is related to my question on how to handle errors from jQuery AJAX calls. Several responses suggested that I use the "error" callback to display any errors from a jQuery AJAX call. I was wondering how to do that using ASP.NET MVC. Is there a way for my controller action to return an error that would be accessible from the "error" callback? The client side code would look something like this:

$.ajax({
   type: "POST",
   url: "MyUrl",
   data: "val1=test",
   success: function(result){
        // Do stuff
   },
   error: function(request,status,errorThrown) {

   }
 });

Best Answer

NOTE: Hey, this was posted before ASP.Net MVC even hit 1.0, and I haven't even looked at the framework since then. You should probably stop upvoting this.

Do something like this:

Response.StatusCode = (int)HttpStatusCode.BadRequest;
actionResult = this.Content("Error message here");

The status code should change depending on the nature of the error; generally, 4xx for user-generated problems and 5xx for server-side problems.

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Javascript – How to get jQuery to perform a synchronous, rather than asynchronous, Ajax request

From the jQuery documentation: you specify the asynchronous option to be false to get a synchronous Ajax request. Then your callback can set some data before your mother function proceeds.

Here's what your code would look like if changed as suggested:

beforecreate: function (node, targetNode, type, to) {
    jQuery.ajax({
        url: 'http://example.com/catalog/create/' + targetNode.id + '?name=' + encode(to.inp[0].value),
        success: function (result) {
            if (result.isOk == false) alert(result.message);
        },
        async: false
    });
}

Javascript – How to manage a redirect request after a jQuery Ajax call

I read this question and implemented the approach that has been stated regarding setting the response HTTP status code to 278 in order to avoid the browser transparently handling the redirects. Even though this worked, I was a little dissatisfied as it is a bit of a hack.

After more digging around, I ditched this approach and used JSON. In this case, all responses to AJAX requests have the status code 200 and the body of the response contains a JSON object that is constructed on the server. The JavaScript on the client can then use the JSON object to decide what it needs to do.

I had a similar problem to yours. I perform an AJAX request that has 2 possible responses: one that redirects the browser to a new page and one that replaces an existing HTML form on the current page with a new one. The jQuery code to do this looks something like:

$.ajax({
    type: "POST",
    url: reqUrl,
    data: reqBody,
    dataType: "json",
    success: function(data, textStatus) {
        if (data.redirect) {
            // data.redirect contains the string URL to redirect to
            window.location.href = data.redirect;
        } else {
            // data.form contains the HTML for the replacement form
            $("#myform").replaceWith(data.form);
        }
    }
});

The JSON object "data" is constructed on the server to have 2 members: data.redirect and data.form. I found this approach to be much better.

Best Answer

Related Solutions

Javascript – How to get jQuery to perform a synchronous, rather than asynchronous, Ajax request

Javascript – How to manage a redirect request after a jQuery Ajax call

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