adding conditions to the where clause conditionally for incremental filtering the record

Question

User-1355965324 posted

I am trying to give where clause with existing linq conditionally  inside the if condition , But not working please help.

Here is my linq. if cusotmer id and product id   should be  given the where clause only if there is value is being passed .

 public IEnumerable<SalesModel> GetSalesList(DateTime DateFrom, DateTime DateTo, int customerId,int productId)
        {
            IEnumerable<SalesModel> saleslist = 
           (from sales in Context.DailySales
               join customer in Context.Customer on sales.CustomerID   equals  customer.CustomerID
                where  sales.InvoiceDate >= DateFrom   && sales.InvoiceDate  <= DateTo
                if(customerId >0 , sales.CustomerId == customerId )
                If(productId > 0 , sales.ProductID ==  productId)
        select new SalesModel
       {
          Id = sales.id
          ProductID = sales.ProductID,                                                           
          Qty = sales.Qty,
          Rate = sales.Rate,
          InvoiceDate= sales.InvoiceDate,
          Customer = sales.Customer                                                               

            });
            return saleslist;
        }