Can I specify a set of base parameters for a Linq-to-sql DataContext?

Question

I have a LINQ-to-SQL DataContext that represents a parent-child relationship of Products to Prices. I'm iterating through a list of products and retrieving the prices for each one. The problem is that the tables behind both the Products and Prices contain a list of Products or Prices for multiple environments, determined by a 3 field complex key. I want to retrieve the Products and Prices for only one of those environments.

I can do this be specifying a long where clause in each LINQ query consisting of the product key and the complex environment key, something like this:

var price = ( from condition in conditiontype where condition.MaterialNumber == material && condition.Client == "400" && condition.SalesOrg == "1000" && condition.DistributionChannel == "10" select condition.ConditionDetails[0].ConditionValue );

what I'd like to be able to do is to specify the Client, SalesOrg, and DistributionChannel globally for the DataContext so that all I need to specify in the query itself is the Product ID (MaterialNumber). That way when I starting querying our Production environment a simple change to the DataContext will change what environment I'm querying.

Is this possible? Either a brief code sample or pointers to the background theory would be wonderful!

Answer 1

You could have a pre-written Expression<T> which you then have those values in it:

public Expression<Func<int>> GetPrices = p => // do Lambda here

Alternatively you can put properties into your DataContext (remember, it's a partial class so it's easy to extend) which you set and are then read in by your expression.