linq to entities - Convert COUNT SQL query into Entity Framework query -

kindly me how write below sql query entity framework lambda expression:

select count(subcategoryname)     dc_subsystem_asset     subcategoryid=1 , dc_countryid=114 , dc_locationid=1 

assuming have dbcontext set entities, might like:

int count = _context.dc_subsystem_assets.count( =>     a.subcategoryid == 1     && a.dc_countryid == 114     && a.dc_locationid == 1     && a.subcategoryname != null); 

we need a.subcategoryname != null condition, because in sql count(column_name) doesn't include null values in count;