hi,
I am sharing some projects between old style Asp.Net and AspNetCore (.net Framework, not .Net Core).  Without a web.config in AspNetCore I want to configure in code and set 
<sqlServerCatalogNameOverwrites>
    <add key="OldNameCatalog1" value="NewNameCatalog1" />
    <add key="OldNameCatalog2" value="NewNameCatalog2" />
</sqlServerCatalogNameOverwrites>
How do I do that?
Thanks.