values are not passing from datagridview into datarow

When I enter values row by row in datagrdivew,value should pass to datatable

Dim tb As New DataTable("GridTable")
tb.Columns.Add("Name", Type.[GetType]("System.String"))
tb.Columns.Add("Currency", Type.[GetType]("System.String"))
For Each d As DataGridViewRow In dg.Rows
Dim r As DataRow = tb.NewRow()
r("Name") = d.Cells(0).Value 'row1 cell 1
r("Currency") = d.Cells(1).Value 'row1 cell2
tb.Rows.Add(r)
Next

Here newly entering values are not passing from datagridview into datarow