Mgiyuk

Unable to concatenate two IEnumerable lists [duplicate] This question already has an answer here: I am creating a WEB API . I have two IEnumerable lists. And at the end I want to concatenate them. WEB API IEnumerable IEnumerable result; IEnumerable prodDetails = new List<tj_xhqd>(); IEnumerable mainDetails= new List<tj_xhqd>(); int prodInterval, prodCount = 0; int mainInterval, mainCount = 0; prodCount = giveProdCount(msn, dt); if(prodCount==0) { prodDetails = ""; } else if (prodCount<=500) { prodDetails = mdcEntitites.tj_xhqd .Where( m => (m.zdjh == msn) && (m.sjsj >= dt) ) .Select( x => new { MSN = x.zdjh, PingDateTime = x.sjsj, PingValue = x.xhqd } ) .ToList(); } else { prodInterval = prodCount / 500; prodDetails = mdcEntitites.tj_xhqd .AsNoTracking() .Where( m => (m.zdjh == msn) && (m.sjsj >= dt) ) .AsEnumerable() .Select( (x, i) => new { MSN = x.zdjh...