Chart not rendering in IE6

[Kieran]

Hi,

My client has told me that sometimes the charts in their application are not rendering in IE6.

How I've got the charts setup:

There's a RadGrid hooked up to an EntitySpaces DataSource for data retrieval. On the DataBound event on the RadGrid, I'm looping through each row and getting the required data to then place a ChartSeriesItem in each of my two charts. There are two RadComboBoxes (as drop downs), which fire a Rebind on the RadGrid on the SelectedIndexChanged event to update the data. This works fine for me 100% of the time, and my client says that about 75% of the time it works for him. However, he said that in IE6 (their standard browser), it's quite common for the charts to not show after selecting a new value from one of the drop downs. The screen space is still reserved for where the charts would be, resulting in a large blank space, but no data is rendered. All of these controls are housed within an ASP.NET UpdatePanel for partial postbacks. I have not yet been able to replicate this issue on my environment.

Anybody have any suggestions as to what might be happening?

Cheers

[Giuseppe]

Hello Kieran,

We were not able to reproduce the problematic behavior in our local tests based on the provided information. Could you confirm whether the deployment on your test machine and on the machine your customer uses is the same? Showing only some of the images usually happens in web farm environment -- the explanation here is this: the page is served by one machine, which generates the chart image and puts it into the Session. Then the request for the image is served by another machine and it cannot find the image - hence the error message. The solution for web farm environment would be to implement State server or SQL server session state mode or sticky sessions, ensuring that all requests from one user will be handled by the same server (however we are a bit unsure whether that is the problem in this case as generally it is not browser-specific and the problem would be observed in more than 25% of the page loads). 

Unfortunately we will not be able to advise you properly how to proceed without a step-by-step guide or a runnable sample application demonstrating the erroneous issue that we can investigate locally.


All the best,
Freddie
the Telerik team

[Kieran]

Hi Freddie,

Thanks for your help on this. A bit more background on the application: the application is being run in the context of SharePoint (all custom dev is done in UserControls which are then loaded into Web Parts and placed within pages in SharePoint). This would explain why my client is seeing this behaviour but I am not, as their environment has multiple web front end servers (3-4 I believe) while my test environment does not.

Is there anything else I can try other than changing the SessionStateMode? Because the application is running within SharePoint, and there are several other custom applications also running in a similar manner (being run in the context of SharePoint), unfortunately changing the SessionStateMode isn't an option due to the potential conflicts it may have or problems it may cause with other applications.

My apologies for not being able to give exact instructions on how to replicate the issue, but I have not yet been able to replicate it myself.

Cheers,
Kieran

[Giuseppe]

Hi Kieran,

Unfortunately we cannot suggest you additional workarounds for this scenario -- you will need to either change the session state mode (State server or SQL server), or use sticky sessions if your load-balancing environments supports it.


Kind regards,
Freddie
the Telerik team

[Kieran]

Hi Freddie,

Thanks for spending the time to help me with this. Given that I could not replicate the issue, I tried the good old 'stab in the dark' method and removed the UpdatePanel/partial postback functionality. My client has said that everything now works as expected.

Cheers