Implementing MS Charts in ASP.NET MVC3 project

There are many, many ways of creating and showing charts in MVC, and the link you referred to is pretty good IMHO. I'm using c#, but the way I'm doing it is to use an img-tag in the view and point the src-attribute to a Controller action:

<img id="diagram" src="<%=Url.Action("DrawChartImage", "Home") %>" alt="Chart Diagram" />

The controller action returns a FileContentResult:

public ActionResult DrawChartImage()
    {
        using (var chartHelper = new ChartHelper())
        {
            //get data
            var data = GetSomeDataForTheChart();

            //draw chart
            chartHelper.Draw(data);

            //return chart as png image
            return File(chartHelper.Image, "image/png");
        }
    }

The ChartHelper class implements IDisposable and has a helper property (Image) which returns the chart as a file, NOTE this is just sample/snippet code to show what I mean:

public class ChartHelper : IDisposable
{
    private readonly Chart _chart;
    public Chart Chart
    {
        get
        {
            return _chart;
        }
    }

    public byte[] Image
    {
        get
        {
            using (var ms = new MemoryStream())
            {
                _chart.SaveImage(ms);
                return ms.GetBuffer();
            }
        }
    }

    public ChartHelper()
    {
        _chart = new Chart();
        _chart.Height = 300;
        _chart.Width = 800;
        _chart.ImageType = ChartImageType.Png;
        _chart.Titles.Add("some title");
        _chart.Legends.Add("some legend");
        _chart.ChartAreas.Add("some chart area");
    }

    public void Draw(List<Data> data)
    {
        var dataArrays = GetDataArrays(data); //another helper method...

        var series = new Series(tag);
        series.Name = tag;
        series.Legend = "tags";
        series.ChartType = SeriesChartType.Spline;
        series.BorderWidth = 4;

        //sample way to add data below... 
        series.Points.DataBindXY(dataArrays.Item1, dataArrays.Item2);

        _chart.Series.Add(series);
    }

    public void Dispose()
    {
        _chart.Dispose();
    }
}

Works pretty well for me, hope it helps even if it's in C#.

EDIT If you want to create the image/chart in business logic called from your "main" Controller action, maybe you can do something like this where you generate the image/chart and then save it to disk, cache or database and pick it up from the image rendering controller action:

        public ActionResult Index()
    {
        //this is call to your business logic or similar which generates the chart
        byte[] image = GenerateImage();
        //save image to cache, disk or from database
        HttpContext.Cache["image"] = image;
        return View();
    }

    public ActionResult Image()
    {
        //get image from cache, disk or from database
        var image = HttpContext.Cache["image"] as byte[];
        return File(image, "image/png"); 
    }

    //some sample/dummy code to generate image from a template
    private byte[] GenerateImage()
    {
        using (var ms = new MemoryStream())
        {
            using (var image = System.Drawing.Image.FromFile(@"c:/temp/template.png"))
            using (var brush = new SolidBrush(System.Drawing.Color.Black))
            using (var bmp = new System.Drawing.Bitmap(image, image.Width, image.Height))
            using (var g = System.Drawing.Graphics.FromImage(bmp))
            {
                g.DrawString(DateTime.Now.ToLongTimeString(), new Font("Consolas", 10), brush, 10, 10);
                bmp.Save(ms, ImageFormat.Png);
            }
            return ms.ToArray();
        }
    }

And the view would be:

<img src="@Url.Action("Image")"/>