E.g.
Dim table As New DataTable
With table.Columns
.Add("Formatted", GetType(Integer))
.Add("Unformatted", GetType(Integer))
End With
With table.Rows
.Add(1, 1)
.Add(2, 2)
.Add(3, 3)
End With
Me.DataGridView1.DataSource = table
Me.DataGridView1.Columns(0).DefaultCellStyle.Format = "\P00000"