//Version 1: SqlServer Timeout Exception with .ToList()

var withdrawals = (from order in orderDc.Orders
where order.Status == (int) OrderStatus.Delivered && order.IsAdminOrder != true && order.DeliveryDate >= fromDt && order.DeliveryDate <= toDt
group order by order.SystemId
into wdResult
                    select new PriceModel()
                    {
                        Price = wdResult.Sum(q => q.WholesalePrice.GetValueOrDefault()),
                        OrderCnt = wdResult.Count(),
                        SystemId = wdResult.Key.GetValueOrDefault()
                    }).ToList();


//Version 2: without .ToList() - executed within a second, 3 SQL queries due to no lazy loading


var withdrawals = (from order in orderDc.Orders
where order.Status == (int) OrderStatus.Delivered && order.IsAdminOrder != true && order.DeliveryDate >= fromDt && order.DeliveryDate <= toDt
group order by order.SystemId
into wdResult
                    select new PriceModel()
                    {
                        Price = wdResult.Sum(q => q.WholesalePrice.GetValueOrDefault()),
                        OrderCnt = wdResult.Count(),
                        SystemId = wdResult.Key.GetValueOrDefault()
                    });

foreach(var systemid in Systems){
   var wd = withdrawals.FirstOrDefault(q => q.SystemId == allSystem.Key);
   //more code...
}