LINQ to SQL - Dynamically Constructing Queries - Um... No!
time to read 2 min | 336 words

Mike Taulty is talking about constructing queries dynamically in Linq to SQL. Sorry, but my response to that is Yuck! Here is the code that he shows:

  NorthwindDataContext ctx = new NorthwindDataContext("server=.;database=northwind");
    
       var query = from c in ctx.Customers
                   where c.Country == "Germany"     
                   select c;
    
       if (RuntimeCriterionOneApplies()) 
       {
        query = from c in query
                where c.City == "Berlin"     
                select c;
       }
    
       if (RuntimeCriterionTwoApplies())
       {
        query = from c in query
                where c.Orders.Sum(o => o.Freight) > 100
                select c;
       }
    
       foreach (Customer c in query)
       {
        Console.WriteLine(c.CustomerID);
       }

This is not constructing queries dynamically, it is choosing a query dynamically. This isn't what I talk about when I am talking about constructing a query dynamically. You can look here as what I consider a complex query that is being constructed dynamically.

Mike, how would you handle that scenario in Linq?

Update:  I really should pay more attention when I am reading the code. Sorry Mike, the code that you have will work for the scenario that I have. I don't think that the syntax is very elegant for this scenario, but it will work. I missed the "from q in query" and read is as if a new query were constructed in each if.

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