C# RDLC sub report how to expand / collapse all the records of sub report

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C++

I have created a report containing a sub report. User can click on the + sign to expand a record. I need to add a "Expand All / Collapse All" function. When user click on Expand All button, all the records of the main report should be expanded at once.

Please guide me in this regard...

What I have tried:

I have tried parameters passing but in vain...