Question

I have a HashSet containing a list int int ids for items which must be selected.

HashSet<int> SelectedItems = new HashSet<int>()

The complete list of items is loaded by a LINQ to SQL statement.
I will be populating an ObservableCollection of the following:

public class DataItem
{
    public int Id { get; private set; }
    public name String { get; private set; }
    public bool IsSelected { get; set; }
}

The IsSelected property must be set to true if the Id is in the HashSet, otherwise it must be set to false;

Here is my LINQ query:

var items =
    from c in itemsContext.DataItems
    where (c.Latest == true)
    select c;

How can I join the HashSet into the above query to achieve the result I desire?

Thanks

PS: I am sorry but I do not know why the code blocks have been formatted incorrectly.

Answer 1

if i’m understanding your question properly i.e. dataitems corresponding to selecteditems in memmory…
Then use contains…

from dataItem in context.DataItems
where dataItem.Latest && SelectedItems.Contains(dataItem.Id)
select dataItem;