How can I convert anonymous type to strong type in LINQ?

Question

I have an array of ListViewItems ( ListViewItem[] ), where I store a SalesOrderMaster object in each ListViewItem.Tag for later reference.

I ha

Answer 1

I see nobody has addressed your need to convert an anonymous type to a named type explicitly, so here goes... By using "select new { }" you are creating an anonymous type, but you don't need to. You can write your query like this:

List orders = 
    (from item in (e.Argument as ListViewItem[]).AsParallel() 
    select (SalesOrderMaster)item.Tag)
    .Distinct()
    .ToList();

Notice that the query selects (SalesOrderMaster)item.Tag without new { }, so it doesn't create an anonymous type. Also note I added ToList() since you want a List.

This solves your anonymous type problem. However, I agree with Mark and Guffa that using a parallel query here isn't you best option. To use HashSet as Guffa suggested, you can do this:

IEnumerable query = 
    from item in (ListViewItem[])e.Argument
    select (SalesOrderMaster)item.Tag;

HashSet orders = new HashSet(query);

(I avoided using var so the returned types are clear in the examples.)