Fastest way to add to a list elements not in second list

Question

I have 2 listBoxes with BindingLists as their data sources. The idea is to make a List builder (as MSDN names it), where first listBox shows currently added columns and second listBox shows the rest of available columns. First list contains ViewColumn objects, while the other list contains strings.
I load chosen columns into first listBox from database and then I want to load the rest of available columns into the second listBox (the list itself comes from another place in database). Considering there are no limits on the number of columns, I want to do that in the fastest way possible - what would that be?
Here's some code to visualize that:

ViewTable _view;
BindingList<ViewColumn> _viewColumns = new BindingList<ViewColumn>();
BindingList<string> _detailsColumns = new BindingList<string>();

void CustomInitialize()
{
    _view = //get view and its columns

    _viewColumns = new BindingList<ViewColumn>(_view.Columns);
    listBox_CurrentColumns.DataSource = _viewColumns;
    listBox_CurrentColumns.DisplayMember = "Name";

    var detailsTable = //get the list of available columns
    foreach (var row in detailsTable)
    {
        //TODO: if _viewColumns does not contain this value, add it to _detailsColumns
            _detailsColumns.Add(row.ColumnName);
    }

    listBox_AvailableColumns.DataSource = _detailsColumns;
}

Answer 1

I think you want to do something like:

_detailsColumns = _allColumns.Except(_viewColumns.Select(c => c.Name))

This should get you all entries in the _allColumns collection excluding the entries in the _viewColumns collection. I assume here that _allColumns contains the overall collection of possible columns.