The first Report has loaded  default Report Parameters 'Select All'

Hello xiang,

This is a setting that must be applied on designing the report. All values can be selected initially by specifying their IDs (ValueMember values as default values for the report parameter).

For more details, please check Specifying Default Values for a MultiValue Parameter.


User functions can be used in the Standalone Report Designer, by loading an assembly with the custom code in it - Extending Report Designer.


I hope this information is helpful.

Regards,
Stef
Telerik

After searching for the same answer and only reading answers pointing to documentation.. which is OK, but not hugely helpful, I decided to post the way I handle this.

If the Reporting parameter is being loaded from a data source then it's very simple to do this using the GUI / report parameter properties.

Just set the Report parameter value to  "= AllValues(Fields.XX)"    

"Fields.XX" is the value that is set in the  "AvailableValues" ,  "ValueMember" property. 

It's that easy.