Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
'select the values of checkboxes from the Grid
Dim i As Integer
Dim li As ListItem
Dim row As GridViewRow = GridView1.SelectedRow
For i = 0 To GridView1.Rows.Count - 1
If CType(GridView1.Rows(i).FindControl("chkSelection"), CheckBox).Checked() Then
li = New ListItem(row.Cells(i).Text)
ListBox1.Items.Add(li)
End If
Next