How to filter a DataTable programmatically

I need to solve a very very simple filter problem, but I'm new using DataTables, DataRows and so on. The solution I propo开发者_如何学运维sed smells a lot. I'm pretty sure that is a better way to implement it.

Here is the simple problem explained:

I have two dataTables called branches and changesets. The dataTable called branches has all the entries in the system, and I need to filter those branches that are not referenced in the changeset entries. A changeset references a branch in a field called FIDBRANCH.

For example. Suppose a dateTable with 6 branches and 3 changesets. Only branches with ids 4 and 5 are referenced.

BRANCHES  
1         
2         
3
4
5
6

CHANGESETS
references to branch 4
references to branch 5
references to branch 5

The result would be the branches dataset filtered only having branches 4 and 5.

This is my bad approach:

private void FilterUnusedBranches(DataTable branches, DataTable changesets)
{
        // index referenced branch ids
        ArrayList branchIds = new ArrayList();

        foreach (DataRow row in changesets.Rows)
        {
            long id = Convert.ToInt64(row["FIDBRANCH"]);
            branchIds.Add(id);
        }

        IList<DataRow> notNeededRows = new List<DataRow>();

        // get a list of non-referenced rows
        foreach (DataRow row in branches.Rows)
        {
            long id = Convert.ToInt64(row["BRID"]);

            if (!branchIds.Contains(id))
            {
                notNeededRows.Add(row);
            }
        }

        // remove not needed rows
        foreach (DataRow row in notNeededRows)
        {
            branches.Rows.Remove(row);
        }
}

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You my wish to create a DataRelation between the tow data tables.

This may help you... http://social.msdn.microsoft.com/Forums/en/adodotnetdataproviders/thread/f122d7f4-3b7d-4d93-bd0f-8bb57cd990a4