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There's no way to do this. RHistory library of Eikon COM APIs can only be used in Excel VBA, as it has a dependency on Eikon Excel COM add-in.
Connect to Datastream with the Eikon .com or .net API
Date flter Screener or RSearch
manual for Eikon C# API
DLL not found - only while debuggin
How to get access to your .net API and retrieve real time data?