c# - Charting in ASP.Net MVC 3

Question

I'm using Chart web helper in ASP.Net MVC 3. I have seen a range of shiny images online showing capabilities of this API, but there is hardly any documentation on how to style the charts. For example, I need to display labels outside of the chart, I'd like to specify percentage, rather than decimal values, etc.

There is a webforms project for download: http://weblogs.asp.net/scottgu/archive/2010/02/07/built-in-charting-controls-vs-2010-and-net-4-series.aspx and very simple class documentation that explains how to assign values and specify basic dimensions.

I understand that no books have been published yet on MVC 3, but surely there should be some sort of documentation explaining how to use the tool?

Thank you

EDIT:

From what I have read, ASP.Net MVC 3 either took a step back with charting tool by removing ability to style charts, or it has not been documented at all. Came across this article: http://forums.asp.net/t/1620783.aspx/1?ASP+NET+MVC+3+Beta+Chart+Helper+Styling+Please+Help+ , a very similar issue is described there.

EDIT 2: It appears that Microsoft have partially implemented MSCharts functionality in MVC 3. In order to use MSCharts, the System.Web.DataVisualization assembly must be imported and registered in web.configuration file. T

This way, requests are sent from view to controllers. Controllers generate image of a graph and pass back an image result. Result is then displayed in the view. This is useful as it provides some sort of seperation. I still don't understand why System.WebHelpers.Chart does not already offer this functionality, but hopefully it will be addressed in near future.

EDIT 3: Few more points to make. Don't construct your graphs in the view - they should be served by a controller. If you do decide to use views for constructing graphs, then make sure you update web.config in Views folder to include <add namespace="System.Web.UI.DataVisualization"/> in the namespace section. Names of assemblies and namespaces are slightly confusing. Assembly is called: System.Web.DataVisualization when namespace is called System.Web.UI.DataVisualization. Finally I think that charting API is great, it serves images which means that charts will be accessible from all web browsers. Quality of the charts is great. I have looked at alternatives such as Fusion Charts, HighCharts and few other jQuery/JavaScript/Flash powered charts. They all try to take ￡300-￡1000 from you without trying to meet the most basic needs of developers.

Answer 1

The chart controls are based off a previously separate project called MS Chart.

Alex Gorev's Blog (MSFT lead dev for the project): http://blogs.msdn.com/b/alexgor/

MS Chart Forums: http://social.msdn.microsoft.com/Forums/en-US/MSWinWebChart/

Documentation on MSDN: http://msdn.microsoft.com/en-us/library/dd456632(VS.100).aspx

The posts seem a bit out of date, but the API is pretty much the same between MS Chart and the new Data Visualization libraries.

To address your example questions:

1) To display labels outside the chart, each Series object has a dictionary array of properties.

series["PieLabelStyle"] = "Outside";

2) To specify percentages rather than raw values, the Series object's Label property takes a formatting string.

series.Label = "#PERCENT{P0}"

These custom attributes are available in detail at http://msdn.microsoft.com/en-us/library/dd456764.aspx.

EDIT: Adding Code Example

Okay, here's a full code example. I'm using System.Web.DataVisualization v4.0.0.0, so this should be current with MVC 3. The series listed above isn't the actual Chart.Series properties (that's a SeriesCollection). It's the individual series that you're adding to that collection.

public ActionResult TestForSOExample()
{
  // slug in some data
  var data = new Dictionary<string, float>
        {
            {"test", 10.023f},
            {"test2", 20.020f},
            {"test3", 19.203f},
            {"test4", 4.039f},
            {"test5", 5.343f}
    };


  var chart = new Chart();

  var area = new ChartArea();
  // configure your chart area (dimensions, etc) here.
  chart.ChartAreas.Add(area);

  // create and customize your data series.
  var series = new Series();
  foreach (var item in data)
  {
        series.Points.AddXY(item.Key, item.Value);
    }
  series.Label = "#PERCENT{P0}";
  series.Font = new Font("Segoe UI", 8.0f, FontStyle.Bold);
  series.ChartType = SeriesChartType.Pie;
  series["PieLabelStyle"] = "Outside";

  chart.Series.Add(series);

  var returnStream = new MemoryStream();
  chart.ImageType = ChartImageType.Png;
  chart.SaveImage(returnStream);
  returnStream.Position = 0;
  return new FileStreamResult(returnStream, "image/png");
}

When you call up the controller's action, you're presented with the following images.