Question

I perform a query on a table Installation to get a list of Ids that are needed to query a table Product on a different database (before you ask, it has to be this way, can’t query across dbs). Here’s what the list looks like:

class Installation 
{
    Guid InstallationId
    Guid ProductId
}

List<Installation> installs;

I don’t have any problems using this list for the query in to the Product table which looks like this:

var prods = (from p in context.Product 
             where installs.Select(i => i.ProductId).Contains(p.ProductId)
             select new
             {
                ProductNumber = p.ProductNumber
                // How do I get InstallationId from installs??
             }).ToList();

What I need to know is how I can retrieve InstallationId from the list and store it in the new list?

Thanks in advance.

Answer 1

A slight refactoring of Jason’s answer to allow for the LinqToSql exception.

var products = (from product in context.Product                
                where installs.Select(i => i.ProductId).Contains(p.ProductId)
                select product).ToList()

var installedProducts = (from product in products
                         join install in installs
                         on install.ProductId equals product.ProductId
                         select new 
                         {
                             ProductNumber = product.ProductNumber,
                             InstallationId = install.InstallationId
                         }).ToList();