c# - Formula conditional EPPlus -

i'm trying add file column conditional formula... cell stay blank or formula show string.

i saw 2 possibilities, using _formatrangeaddress or each data of cell... file can have 150 000+ rows...

 var _formatrangeaddress = new exceladdress("c1:cxxxx,d1:dxxxx");          string _statement = "si(c2=d2;point(d2 c2);linestring(d2 c2,d3 c3)";         var _cond4 = worksheet.conditionalformatting.addexpression(_formatrangeaddress);         _cond4.style.fill.patterntype = officeopenxml.style.excelfillstyle.solid;         _cond4.formula = _statement; 

any ideas how can make formula works? thanks.