ASPX page within a .aspx page with iframe throws 500.23 error - asp.net

Question

I'm trying to embed a ChartModule.aspx page within a Default.aspx page using an iframe.
The ChartModule has a button event which updates a chart. The ChartModule has its own ChartsModule.cs.
I'm getting this error:
HTTP Error 500.23 - Internal Server Error An ASP.NET setting has been
detected that does not apply in Integrated managed pipeline mode.Most
likely causes:
•This application defines configuration in the system.web/httpHandlers
section. Things you can try: •Migrate the configuration to the
system.webServer/handlers section. You can do so manually or by using
AppCmd from the command line. For example, from the IIS Express
install directory, run appcmd migrate config "Default Web Site/".
Using AppCmd to migrate your application will enable it to work in
Integrated mode. It will continue to work in Classic mode and on
previous versions of IIS. •If you are certain that it is OK to ignore
this error, it can be disabled by setting
system.webServer/validation#validateIntegratedModeConfiguration to
false. •Alternatively, switch the application to a Classic mode
application pool. For example, from the IIS Express install directory,
run appcmd set app "Default Web Site/"
/applicationPool:"Clr4ClassicAppPool". Only do this if you are unable
to migrate your application.
Detailed Error Information: Module ConfigurationValidationModule
Notification BeginRequest Handler
PageHandlerFactory-Integrated-4.0 Error Code 0x80070032 Requested
URL http://localhost:4161/Default.aspx Physical Path
C:\Documents and
Settings\singhm\Desktop\Temp\Trial2\Trial2\Default.aspx Logon Method
Not yet determined Logon User Not yet determined Request Tracing
Directory
Why is this?

Answer 1

While this may not answer your question directly, here is a thought:
If you have the option, consider turning ChartModule.aspx into a UserControl (ascx), which acts just like another "page" (same lifecycle, its own codebehind file, etc) but integrates more cleanly into an existing aspx page. The above link should be a good introduction to creating and using UserControls.

Answer 2

The error message contains a clue to the solution:
setting system.webServer/validation#validateIntegratedModeConfiguration to false
So make sure the following is present in your web.config:
<validation validateIntegratedModeConfiguration="false"/>
For example:
<configuration>
<!-- your existing settings -->
<system.webServer>
<!-- Add this to here.... -->
<validation validateIntegratedModeConfiguration="false"/>
</system.webServer>
</configuration>
IIS 7 and ASP.NET are quite helpful these days with regard to to error messages and hints contained therein so you should take the time to read them.

Answer 3

I would really recommend using a usercontrol page instead of iframes in asp.net this way you can bind that usercontrol by doing
public override DataBind()
in that you can pass anything into that usercontrol page like refresh data, load certain data, etc..