Unable to get contract parameters if i extend SrsReportDataProviderPreProcess in D365

Hi All,

I am using D365 version (Microsoft Dynamics 365 for Finance and Operations (7.3))

I am creating a custom report and if i use SrsReportDataProviderPreProcess  i am not able to get the contract parameters 
currently i am taking fromdate and todate parameters in my report.
And if i use SRSReportDataProviderBase i am able to get the same parameters from my contract class without any issue.
I am facing performance issues for larger period  in my report and i optimized my code to max level and thought of using SrsReportDataProviderPreProcess  
and i am not able to get the parameters if i use SrsReportDataProviderPreProcess.
Please advice,
Thanks in advance,