Report works in Designer until I add a parameter, then "Exception thrown by target of invocation"

[WombatEd]

My report was working fine using a SqlDataSource that used a SELECT without any WHERE clause.  Then I changed it to use an ObjectDataSource method that uses parameters to generate a WHERE clause, and my report now fails.  The ObjectDataSource method works fine when invoked by my WebForms, and I tried putting a breakpoint in my business object's Select method, and I never got there, so I'm pretty sure it's not a problem within my object.

When I try to "preview" the report, the designer shows me this error message:
    An error has occurred while processing Report 'MyReport':
    Exception has been thrown by the target of an invocation.
    --------------------- InnerException ----------------------
    Object reference not set to an instance of an object.

I based my implementation upon this tutorial: http://tv.telerik.com/watch/reporting/objectdatasource/using-parameters-with-objectdatasource-component

I'm a Reporting newbie, and I need to learn how to debug reports.  (Apparently you can't simply step through them using the debugger.)  So any tips on how to investigate report bugs would be gratefully accepted.

[WombatEd]

This problem only occurs if I use an ObjectDataSource.  If I use a SqlDataSource, with the same parameter, the report works.

[WombatEd]

I've submitted this as a Support Ticket: #382736.

[Daniel]

Have you got any valid solution?

Thanks
Daniel

[Ayman]

Any solution ?!

[WombatEd]

This problem was only appearing in the designer's preview modes.  When I added code to programmatically assign the ObjectDataSource, the problem went away.

[Jo]

I am having a same problem which WombatEd posted at the beginning of this post, I am using ObjectDataSource with Sharepoimt List.
I am trying to create a report in telerik reporting and upload it in  sharepoint as a webpart.
I also refer the video suggested in above post and I am doing exactly the same, however, When I try to "preview" the report, the designer shows me this error message:

    An error has occurred while processing Report 'MyReport':
    Exception has been thrown by the target of an invocation.
    --------------------- InnerException ----------------------
    Object reference not set to an instance of an object. 

Can anyone give me the fix.. 
And also Is there a way to use more than one objectdatasource in a Report.

Thanks In advance..

[Steve]

Hello Nu,

In the case of report designer/preview the current application is devenv.exe so reading the  ConfigurationManager.ConnectionStrings from the report that is previewed will get all connection strings defined in the devenv.exe.config file. SqlDataSource works, because we connect directly to the Sql server, while in the ObjectDataSource, you're using external custom methods that can't resolve the connectionstring for the devenv.exe runtime. 

In order to avoid this behavior you have several options:

1. Hard code the connection string
2. Simply use an actual application to view your reports in runtime instead of the Previews.
3. Use SqlDataSource instead that will handle the connection strings

Regards,
Steve
the Telerik team