The wrong code in your case:
cbo.DataSource = StronglyDataTable.OrderBy(x => x.pName)).Select(x => new { x.pID, x.pName });
cbo.DisplayMember = "pName";
cbo.ValueMember = "pID";
The correct code:
cbo.DisplayMember = "pName";
cbo.ValueMember = "pID";
cbo.DataSource = StronglyDataTable.OrderBy(x => x.pName)).Select(x => new { x.pID, x.pName });