Steema Central

There is a onhelp SetCurrentZoom method.
This is the sample code.

private void Page_Load(object sender, System.EventArgs e)
{
MemoryStream tmpChart;

if (Session["ch1"]==null)
{
WebChart1.Chart[0].FillSampleValues();
tmpChart=new MemoryStream();
WebChart1.Chart.Export.Template.Save(tmpChart);
//save template to a Session variable
Session.Add("ch1",tmpChart);
}
else
{
//retrieve the session stored Chart
tmpChart=(MemoryStream)Session["ch1"];
//set the Stream position to 0 as the last read/write
//will have moved the position to the end of the stream
tmpChart.Position=0;
//import saved Chart
WebChart1.Chart.Import.Template.Load(tmpChart);
CheckZoom(WebChart1);
}
}

private void CheckZoom(WebChart wChart)
{
ArrayList zoomedState=(ArrayList)Session[wChart.ID+"Zoomed"];
zoomedState=((Steema.TeeChart.Tools.ZoomTool)wChart.Chart.Tools[0]).SetCurrentZoom(Request,zoomedState,DeterminePostBackMode());
if (zoomedState==null)
Session.Remove(wChart.ID+"Zoomed");
else
Session.Add(wChart.ID+"Zoomed",zoomedState);
}

But when I use this code, nothing happen.
It could not zoom in postback and !postback.
How can I use this code in my program?
Thank you.

Hi scott,

You should do exactly as shown in the example at the ASP.NET demo included with TeeChart's installation. You can find the demo at C:\Program Files\Steema Software\TeeChart for .NET v2\TeeChartForNET (Default English installation path). Does this demo work fine at your end?

Thank you Narcís,
I knew there is a Zoom sample in file WebAppZoomChart.aspx.
But I can't find any thing about DeterminePostBackModebout int WebAppZoomChart.aspx.

Hi scott,

Does that example work fine at your end? Does it behave as you expect?

Please see the step
1.Web page load
2.Zoom the WebChart
3.Click Button1 the WebChrt.Series[0] will change value, but WebChart still in the step 2 zoom scale.

My problem is when I already zoomed a webchart, then I update webchart data.
But the webchart still in last zoom scale.
When I update webchart data, I try to use Chart.Zoom.Undo but it still can't back normal zoom.

protected void Page_Load(object sender, EventArgs e)
{
MemoryStream tmpChart;

WebChart1.Chart.Series[0].FillSampleValues(200);
if (Session["ch1"] == null)
{
WebChart1.Chart[0].FillSampleValues();
tmpChart = new MemoryStream();
WebChart1.Chart.Export.Template.Save(tmpChart);
//save template to a Session variable
Session.Add("ch1", tmpChart);
}
else
{
//retrieve the session stored Chart
tmpChart = (MemoryStream)Session["ch1"];
//set the Stream position to 0 as the last read/write
//will have moved the position to the end of the stream
tmpChart.Position = 0;
//import saved Chart
WebChart1.Chart.Import.Template.Load(tmpChart);
CheckZoom(WebChart1);
}

}

private void CheckZoom(WebChart wChart)
{
ArrayList zoomedState = (ArrayList)Session[wChart.ID + "Zoomed"];
zoomedState = ((Steema.TeeChart.Tools.ZoomTool)wChart.Chart.Tools[0]).SetCurrentZoom(Request, zoomedState);

if (zoomedState == null)
Session.Remove(wChart.ID + "Zoomed");
else
Session.Add(wChart.ID + "Zoomed", zoomedState);
}

protected void Button1_Click(object sender, EventArgs e)
{
//WebChart1.Chart.Zoom.Undo(); --> I try to use Zoom.Undo()
WebChart1.Chart[0].FillSampleValues();
}

Hi scott,

In that case you could implement button's code like below. Setting axes to automatic you unzoom the chart.

Narcís, thank you very much. It really helps me.

I stuck this function a little time.

The resolve is so easy.

I need to study in TeeChart. And it is a good 'Object'.