Since Telerik Reporting Q1 2010 version, when the report enters the processing stage, report parameter values are validated against their validation properties (no matter if the parameter is visible or not). If one or more parameters do not have valid values, processing is aborted.
The validation properties include the type of the parameter, is it a single or multi-value, is its value among the available values (if such are defined), is null value allowed etc...
Although we're not sure of your exact scenario, you should be able to convert the guid to string in the subreport parameter expression directly by using the CStr() built-in function
, thus avoiding changes in your database.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items