How to correctly filter a datatable (datatable.select)

The accepted answer is correct, though it should have been given in vb.net to better benefit the one that asked the question. Here it is in VB.Net:

Dim dt As New DataTable:Dim dv As New DataView(dt):dv.RowStateFilter = "GroupingID = 0":DataGridView1.DataSource = dv

dt.Select() returns an array of DataRows.

Why don't you use a DataView?

 DataView dv = new DataView(dt);
 dv.RowFilter = "GroupingID = 0";
 GridView1.DataSource = dv;

Junt in case... Think you've got a small typo in your VB.NET code. It should be dv.RowFilter instead of dv.RowStateFilter, so:

Dim dt As New DataTable
Dim dv As New DataView(dt)
dv.RowFilter = "GroupingID = 0"
DataGridView1.DataSource = dv