Printing chart using TempChart=Session

[Joe]

I have a WebChart which displays fine but fails to print. TempChart is set to Session, and my GetChart.aspx Page_Load is adapted from Tutorial 9 as follows:

private void Page_Load(object sender, System.EventArgs e)
{
string chartName=Request.QueryString["Chart"];
if (Session[chartName]!=null)
{
System.IO.MemoryStream chartStream = new System.IO.MemoryStream();
chartStream=((System.IO.MemoryStream)Session[chartName]);
Response.OutputStream.Write(chartStream.ToArray(),0,(int)chartStream.Length);
//chartStream.Close();
//Session.Remove(chartName);
}
}

Note that I don't close the stream or remove it from the session since the print operation will request the same chart. On trying to print any page that includes a WebChart, the chart does not print and, even worse, other session data is either removed or overwritten.

Vincent Frisina
Synapcent

[Pep]

Hi Vincent,

does the example included in the TeeChart for Net v1 installation under :
C:\Program Files\Steema Software\TeeChart for .NET v1\TeeChartForNET\WebForm works fine for you ?

[Joe]

The example code does not work for me. The code I had originally posted was that exact code with the line to close and remove the stream removed so that the stream would still be open and available when the browser print operation requested the stream again. With or without closing the stream, my session state is lost when I try to print a page containing a web chart.

What I am most concerned about is that simply trying to print any page that inclues a webchart causes me to loose my session state.

I also experimented with simply returning from my Page_Load method without manipulating the stream in case I was doing something wrong there. Of course, the chart did not display since I never sent the data to the client, but I saw I was still losing my session state. I then trimmed down even further by not adding any data or in any way manipulating web chart on the page I was trying to print. All it showed was the default empty chart. However, when I tried to print the page containing that web chart my session state was again lost and the chart did not print.

[Christopher]

Hi Vicent,

I'm using the latest TeeChart for .NET, version 1.1.1644.16795.

In a new ASP.NET app I added in the standard GetChart.aspx. I then added a WebChart to WebForm1.aspx and set the TempChart property to "Session". I then added the following code to WebForm1:

Code: Select all

private Steema.TeeChart.Chart Chart1;
	
private void Page_Load(object sender, System.EventArgs e)
{
	Chart1 = WebChart1.Chart;
	MemoryStream tmpChart=new MemoryStream();

	Chart1[0].FillSampleValues(20);

	if (Session["Chart1"]==null) {
		Chart1.Export.Template.Save(tmpChart);
		Session.Add("Chart1",tmpChart);
	}
	else {
		tmpChart=(MemoryStream)Session["Chart1"];
		tmpChart.Position=0;
		Chart1.Import.Template.Load(tmpChart);
	}
}

I then run this project and selected IE's File->Print... menu option. I then printed to a PDF file using a free printer driver available from http://www.pdf995.com/download.html. I have uploaded the results to news://www.berneda.com/steema.public.attachments.

Are you able to reproduce this behaviour at your end?