Rendering Chart from WebService

[Alexander]

Got html from WebServices.
With these additional settings to chart control:

chert.UseSession =

 

false;

 

chert.TempImagesFolder =

 

"~/TempImages/";

 

Having problem getting chart html from WebService. My task it to have it on client side from WS.
Failed with both of implementations below:
1.

 

 

 

[WebMethod]
public string GetChart()
{
   RadChart chert = new RadChart();
   chert.ID = "olapChart";

string result = string.Empty;
using (MemoryStream stream = new MemoryStream())
{
       StreamWriter writer = new StreamWriter(stream);
       HtmlTextWriter htmlWriter = new HtmlTextWriter(writer);
       chert.RenderControl(htmlWriter);
       System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
       writer.Flush();
       result = encoding.GetString(stream.ToArray());
 }

Having "Object reference not set to an instance of an object." on call chert.RenderControl(htmlWriter);

2.

[WebMethod]
        public string GetChart()
        {
           return GetChartRendered(chert);
        }

        private string GetChartRendered(RadChart chert)
        {
            string result = string.Empty;

            TempRenderer pageHolder = new TempRenderer();
            HtmlForm tempForm = new HtmlForm();
            tempForm.ID = "TempForm";
            pageHolder.Controls.Add(tempForm);
            tempForm.Controls.Add(new ScriptManager());
            tempForm.Controls.Add(chert);

            StringWriter output = new StringWriter();
            HttpContext.Current.Server.Execute(pageHolder, output, false);

            result = output.ToString();
            return result;
        }

        public partial class TempRenderer : System.Web.UI.Page
        {
        }

Having "Error executing child request for handler 'ChartTest.TempRenderer'" there on Server.Execute.

3. Eventually created just page "chart.aspx" wiht just single chart control decalred

<

 

 

telerik:RadChart ID="chert" runat="server" Width="500px" Height="290px" EnableViewState="false" SkinsOverrideStyles="false" ></telerik:RadChart>

 

 

 

and trying this in WebMethod:

StringWriter output = new StringWriter();
HttpContext.Current.Server.Execute("chart.aspx", output, false);
string result = output.ToString();

Having ex:" Error executing child request for chart.aspx."

As I understand the reason of all these exceptions is ChartImage.axd
handler.

If somebody can help - please, it's very urgent.
Thank you.

 

 

[Bartholomeo Rocca]

Hello Alexander,

I do not think that this would be possible as the chart image is not just a bunch of html but it is actually served by the ChartImage.axd HttpHandler.

You might try saving the chart image to a stream via RadChart.Save(...) method and process the result with your service.


Greetings,
Bart.

[kulashaker]

Hi, I know this thread is quite old, but I actually need to run Chart.RenderControl.

Reason is that I need to extract the ImageMap collection from the resulting HTML that RenderControl produces. I know it sounds messy but there is no property that exposes the ImageMap in the RadChart control.

Is there another way of doing this?

Cheers
Bruce