Pass values from MVC controller to javascript code

Question

I need to pass list/json/array of dates information to a Jquery UI Datepicker dynamically through a jsonresult in a MVC controller.

Following the link below, I am able to highlight selected dates in the datepicker control. http://jquerybyexample.blogspot.com/2012/05/highlight-specific-dates-in-jquery-ui.html

    < script type ="text/javascript">
    $(document).ready( function () {

    var SelectedDates = {};
    SelectedDates[ new Date('05/28/2012' )] = new Date( '05/28/2012' );
    SelectedDates[ new Date('05/29/2012' )] = new Date( '05/29/2012' );
    SelectedDates[ new Date('05/30/2012' )] = new Date( '05/30/2012' );
    //want to replace the above three lines with code to get dates dynamically
    //from controller

    $( '#releasedate' ).datepicker({
        dateFormat: "mm/dd/yy" ,
        numberOfMonths: 3,
        duration: "fast" ,           
        minDate: new Date(),
        maxDate: "+90" ,
    beforeShowDay: function (date) {
        var Highlight = SelectedDates[date];
        if (Highlight) {
            return [true , "Highlighted", Highlight];
        }
        else {
            return [true , '', '' ];
        }
    }
});

The above code will highlight those specific three dates on the calendar control(UIDatepicker).Instead of hard coding dates like above... My challenge is to get these dates dynamically from a controller and pass it on to the var SelectedDates in javascript above.

Controller jsonresult code:

  public JsonResult GetReleasedDates(string Genre)
{

    var relDates = service.GetDates(Genre)//code to get the dates here

    return Json(relDates, JsonRequestBehavior .AllowGet);

    //relDates will have the dates needed to pass to the datepicker control.

}

Thanks for the help.

Answer 1

The first possibility is to use a model that will be directly serialized into JSON:

public ActionResult Index()
{
    // TODO: obviously those will come from your service layer
    var selectedDates = new Dictionary<string, DateTime> 
    { 
        { new DateTime(2012, 5, 28).ToString("yyyy-M-dd"), new DateTime(2012, 5, 28) },
        { new DateTime(2012, 5, 29).ToString("yyyy-M-dd"), new DateTime(2012, 5, 29) },
        { new DateTime(2012, 5, 30).ToString("yyyy-M-dd"), new DateTime(2012, 5, 30) },
    };
    return View(selectedDates);
}

and in the view:

@model IDictionary<string, DateTime>

<script type ="text/javascript">
    $(document).ready(function () {

        var selectedDates = @Html.Raw(Json.Encode(Model));

        $('#releasedate').datepicker({
            dateFormat: "mm/dd/yy",
            numberOfMonths: 3,
            duration: "fast",
            minDate: new Date(),
            maxDate: "+90",
            beforeShowDay: function (date) {
                var key = date.getFullYear() + '-' + (date.getMonth() + 1) + '-' + date.getDate();
                var highlight = selectedDates[key];
                if (highlight) {
                    return [true, "Highlighted", highlight];
                }
                else {
                    return [true, '', ''];
                }
            }
        });
    });
</script>

The other possibility is to use AJAX to retrieve the selectedDates later:

public ActionResult Index()
{
    return View();
}

public ActionResult GetSelectedDates()
{
    // TODO: obviously those will come from your service layer
    var selectedDates = new Dictionary<string, DateTime> 
    { 
        { new DateTime(2012, 5, 28).ToString("yyyy-M-dd"), new DateTime(2012, 5, 28) },
        { new DateTime(2012, 5, 29).ToString("yyyy-M-dd"), new DateTime(2012, 5, 29) },
        { new DateTime(2012, 5, 30).ToString("yyyy-M-dd"), new DateTime(2012, 5, 30) },
    };
    return Json(selectedDates, JsonRequestBehavior.AllowGet);
}

and then:

<script type ="text/javascript">
    $(document).ready(function () {
        $.getJSON('@Url.Action("GetSelectedDates")', function(selectedDates) {
            // Only inside the success callback of the AJAX request you have
            // the selected dates returned by the server, so it is only here
            // that you could wire up your date picker:
            $('#releasedate').datepicker({
                dateFormat: "mm/dd/yy",
                numberOfMonths: 3,
                duration: "fast",
                minDate: new Date(),
                maxDate: "+90",
                beforeShowDay: function (date) {
                    var key = date.getFullYear() + '-' + (date.getMonth() + 1) + '-' + date.getDate();
                    var highlight = selectedDates[key];
                    if (highlight) {
                        return [true, "Highlighted", highlight];
                    }
                    else {
                        return [true, '', ''];
                    }
                }
            });
        });
    });
</script>

Answer 2

There is a library to exchange data from controller to javascript without the need of a further ajax call or inline javascript. If you need the data on every page, you could use it in a filter.

http://jsm.codeplex.com

With the library you could just write the following code in your MVC Controller Action:

// Add the dates as objects to javascript - The object should only contain data
// which should be exposed to the public.
this.AddJavaScriptVariable("DatePickerController.Dates", service.GetDates(Genre));
// Execute the initialization function when the DOM has been loaded
// The function can be in a javascript file
this.AddJavaScriptFunction("DatePickerController.Ready");

Your javascript file could look like this:

var DatePickerController = {
    Dates: null,
    Ready: function() {
        $("#releasedate").datepicker({
            dateFormat: "mm/dd/yy" ,
            numberOfMonths: 3,
            duration: "fast" ,           
            minDate: new Date(),
            maxDate: "+90" ,
            beforeShowDay: function (date) {
                var Highlight = DatePickerController.Dates[date];
                if (Highlight) {
                    return [true , "Highlighted", Highlight];
                }
                else {
                    return [true , '', '' ];
                }
            }
        });
    }
};

Note: You maybe have to create a special model for the dates you pass with this.AddJavaScriptVariable which is compatible to the datepicker.