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Problem with (Sub-)Reports in the VS 2008 SP1 Designer after first time running

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Michael asked on 05 Mar 2009, 12:36 PM

Hello!

Actually I'm testing your Telerik Reporting Product (Telerik_Reporting_2008_3_1402_trial). I have designed a big report (>255 Textboxes ==> I know, that this are many textboxes, but this is real life), so I needed to part the whole report in one main report and in one subreport (don't missunderstand me ==> it is not designed as the master-detail-example yet).

I added a subreport control to the main report and set the reportsource-property to the subreport I created. Then I run my web application in VS 2008 SP1. Everything works fine.

After I close the running web application, Visual Studio tells me, that there are errors and the main report class could/should not be loaded into the designer to prevent data loss.

The two error messages in detail (translated from german VS with google language tools):

1)
german: Der Objektverweis wurde nicht auf eine Objektinstanz festgelegt.

english: Object reference not set to an instance of an object.

2)
german: Die Variable reportZahlung1 wurde nicht deklariert oder nicht zugeordnet.
english: The variable reportZahlung1 has not been declared or not assigned.

So I can't go on with the designing of the report. Interesting is, that when I start the project again, everthing works still fine.

Any suggestions to solve the problem would be very nice.

By

Michael
M

5 Answers, 1 is accepted

answered on 06 Mar 2009, 08:48 AM

Good Morning Steve!

Like you told me, I deleted all data for reportZahlung (incl. statements for control subreport1) and rebuild the projects.
It compiled successfully, but the designer still showed the warning message.

Then I closed VS and directly opened my project in a new instance of visual studio. After that both reports were shown
correctly in the designer. Then I added a subreport control to the main report. But when I want to set the reportsource
property, VS shows me a error message box: "Object reference not set to an instance of an object." ?!?

After that, I delete the hole subreport and added a new one to the project. Then I tried to reference this report with the
reportsource-property, but the same error message appeared.

What should I do?

Bye

Michael

answered on 06 Mar 2009, 10:42 AM

Hello!

Here are some infos I want to complement:

a) We can except that the problem is a problem with my computer respectively the installation. I tested my solution yesterday evening with another notebook. The problem stays the same.

b) A few minutes ago I build a small test project, where I use the same database (MySQL; MySQL Connector 5.2.5), but here I wanted to test, if the problem is a problem of to many textbox in main- and/or subreport in my real life application. So I used only <5 textboxes in main- and subreport. After first time building and debugging, I get the designer error message for the mainreport.

Michael

answered on 18 Mar 2009, 05:14 PM

Hi Michael,

The email support@telerik.com is used for internal purposes only and for sending No-Reply email messages i.e. it is not checked. If you need to send an email with technical inquiry the proper address is clientservice@telerik.com. However we highly recommend using our support ticket system instead, which also allows you to attach your files. Or of course you can also upload them on a live server and post a link in this forum or a support ticket.

Thank you for the understanding.

Regards,
Steve
the Telerik team

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Abdul

commented on 11 Sep 2025, 09:48 AM

Hello,

"I am using the Web Report Designer with a TableAdapter to load and display a large dataset (~200,000 rows). When I preview the report, it takes around 8 minutes to render, or sometimes does not render at all. I would like to understand if Telerik Reporting supports server-side or on-demand data paging during preview to improve performance, and what best practices you recommend for handling large datasets in the Web Report Designer environment."

Note: I'm currently using a DataSet with TableAdapter as the data source, and I’d like to know the recommended approach for implementing data during preview.

Ivet

commented on 12 Sep 2025, 10:32 AM

Hello Michael,

Telerik Reporting does not support server-side or on-demand data paging during report processing or preview. When you preview a report, the entire dataset required by the report (all 200,000 rows in your case) is loaded and processed before any pages are rendered. Paging in the report viewer only affects navigation of already processed pages and does not limit the volume of data retrieved or processed by the report engine.

To optimize performance, filter your data as much as possible before it reaches the report. Use report parameters to limit the dataset retrieved by your TableAdapter. This ensures only the necessary records for the current report context are processed. You can learn more about that from the below articles:

If you need more control over data retrieval, consider switching to the ObjectDataSource component. This allows you to implement custom methods that accept parameters and return only the required subset of data, supporting on-demand logic - ObjectDataSource Component at a Glance - Telerik Reporting

Limit the use of complex expressions, aggregates, and conditional formatting, as these can impact performance with large datasets - Performance Factors at a Glance - Telerik Reporting.

If the provided information doesn't help you could you please send me your project and report with sample data?

If you are hesitant to send your project and report here, you can open a ticket and provide the details there.