Could use some help conceptualizing how to finish implementing a Microsoft Chart w/ drill-down capabilities under MVC

Question

I have most of this figured out, but I am wondering if I need to return a partial page view or just an image.

So, the way drill-down charts need to be implemented under MVC can be seen at: http://geekswithblogs.net/DougLampe/archive/2011/01/23/charts-in-asp.net-mvc-2-with-drill-down.aspx

The key point to make here is that we are leveraging the URL property of a series to navigate 'down a level' on the chart.

public ActionResult HistoricalChartMap(int reportID)
{
    HistoricalChartData chartData = new HistoricalChartData(reportID, string.Format("Chart_{0}", Guid.NewGuid().ToString().Replace('-', 'a')));
    LineChart chart = new LineChart(chartData);

    foreach (Series series in chart.Series)
    {
        string postBackValue = series.PostBackValue;
        series.Url = string.Format("../Chart/HistoricalDrillDown?ReportID={0}&PostBackValue={1}", reportID, postBackValue);
    }

    //Must call SaveImage before GetHtmlImageMap
    var imgStream = new MemoryStream();
    chart.SaveImage(imgStream);
    imgStream.Seek(0, SeekOrigin.Begin);

    string sessionKey = string.Format("HistoricalReport: {0}", reportID);
    Session[sessionKey] = chart;

    // Return the contents of the Stream to the client
    return Content(chart.GetHtmlImageMap("HistoricalChartMap"));
}

Note that the URL points to a method of my ChartController:

public ActionResult HistoricalDrillDown(int reportID, string postBackValue)
{
    string sessionKey = string.Format("HistoricalReport: {0}", reportID);
    LineChart lineChart = (LineChart)Session[sessionKey];
    lineChart.DrillChart(postBackValue);

    var imgStream = new MemoryStream();
    lineChart.SaveImage(imgStream);
    imgStream.Seek(0, SeekOrigin.Begin);

    // Return the contents of the Stream to the client
    return File(imgStream, "image/png");
}

HistoricalDrillDown returns the new ChartImage that I would like to display in my partial view, but I am dropping the ball at this point. How should I go about replacing my current chart image with the image returned? Currently, I am just directed to a new page that has just the chart image on it.

My partial view's markup is like so:

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl" %>
<div id="HistoricalChartDialog">
    <div id="ChartConfigurators">
        <label for="ReportSelector">Historical Chart: </label>
        <select id="ReportSelector" name="ReportSelector"></select>

        <div id="ToggleLegendWrapper">
            <label for="ToggleLegend">Toggle Legend</label>
            <input type="checkbox" id="ToggleLegend" name="ToggleLegend" />
        </div>
    </div>
    <img id="HistoricalChart" src="" alt="" usemap="#HistoricalChartMap" />
</div>

Note the img tag in the middle of this partial view. I would like to update the img's SRC attribute after a user has followed the URL to HistoricalDrillDown.

Taking suggestions. :)

Kind regards.

Answer 1

I opted to do this:

foreach (Series series in lineChart.Series)
{
    series.Url = string.Format("javascript: DrillChart('{0}')", series.PostBackValue);
}

and then handled the logic client-side for replacing the image.