Lets use a simple “Person” model and have a look at the ASP.NET MVC action:

public ActionResult GetPerson(int id)
{
    var person = Context.GetPerson(id);
    return Json(new
                    {
                        success = true,
                        model = new
                                    {
                                        person.Id,
                                        person.Name,
                                        person.Surname,
                                        person.Age,

                                    }
                    });
}

As you can see this returns a DTO (data transfer object) as JSON result and is ready to be consumed via AJAX…

$.getJSON("/Person/1", function(data) {
    if (data.success) {
        $.updateForm(data.model);
    } else {
        alert("An error occurred");
    }
});

All we then need is the magical “$.updateForm” method that contains all the voodoo:

jQuery.updateForm = function(model) {
   // we iterate through all the properties
   for (var property in model) {
        // evaluate the expression to get the value
        var propertyValue = eval("model." + property);
        // and update the field
        $("#" + property).val(propertyValue);
    }
};

Currenty this will work fine for textboxes and textareas as this was all the functionality I needed for now. If anyone extends this for “select”, “checkbox”, “radiobutton” etc… please share with us so I can update this post.

ASP.NET MVC Action Method

public ActionResult GetUsers()
{
     var data = Service.QueryUsers()
           .Select(x => new {value = x.Id, text = x.Name});

      return Json(data);
}

Usage:

var url = "<%=Url.Action("GetUsers", "UserController") %>";

$.getJSON(url, function(data, textstatus) {
        $.populateSelect("#someSelectBox", data);
});

Global Method:

// JQuery Method
jQuery.populateSelect = function(selectId, data) {
    $.each(data, function() {
        var option = new Option(this.text, this.value);
        var dropdownList = $(selectId)[0];
        if ($.browser.msie) {
            dropdownList.add(option);
        } else {
            dropdownList.add(option, null);
        }
    });
};

Removing all Items from a select list is just as simple:

$("#mySelectList")
   .find("option")
   .remove();

And lastly how to Append or Prepend items to the list:

// Add options to the end of a select
$("#mySelectList")
    .append("New Item");

// Add options to the start of a select
$("#mySelectList")
    .prepend("Select...");

The ajaxReload var can then be set to a function that would handle the ajaxCall. These methods would usually be located in a ‘common.js’ file.

// GLOBAL VARS
var ajaxReload = function() { };

$(".ajaxCall").live("click", function(e) {
    e.preventDefault();
    $.get($(this).attr("href"), ajaxReload);
});

$(".yesNoAjaxCall").live("click", function(e) {
    e.preventDefault();
    if (confirm('Are you sure?')) {
        $.get($(this).attr("href"), ajaxReload);
    }
});

The reason behind using ‘live’ instead of ‘bind’ or ‘click’ is because I want to bind all future loaded ‘a’ tags too. Usually ‘bind’ or ‘click’ will only find the static ‘a’ tags that are available on page load.