'Einige Demodaten 
  With DataGridView1
     .Columns.Add("Spalte1", "Spalte 1")
     .Columns.Add("Spalte2", "Spalte 2")
 
     .Rows.Add(New Object() {"1.1", "1.2"})
     .Rows.Add(New Object() {"2.1", "2.2"})
     .Rows.Add(New Object() {"3.1", "3.2"})
 
  End With
 
  'Spalten im 2. Grid entsprechend dem ersten Grid
  For i As Integer = 0 To DataGridView1.Columns.Count - 1
      DataGridView2.Columns.Add _
      (CType(DataGridView1.Columns(i).Clone, DataGridViewColumn))
  Next i

 Private Sub DataGridView1_RowHeaderMouseClick(ByVal sender As Object, _
                ByVal e As System.Windows.Forms.DataGridViewCellMouseEventArgs) _
                Handles DataGridView1.RowHeaderMouseClick
 
    If e.Button = System.Windows.Forms.MouseButtons.Right Then
       With DataGridView1
          Dim values(.Columns.Count - 1) As Object
          'Daten aus Zeile lesen 
          For i As Integer = 0 To .Columns.Count - 1
             values(i) = .Rows(e.RowIndex).Cells(i).Value
          Next i
          'Daten als neue Zeile im 2.Grid anfügen
          DataGridView2.Rows.Add(values)
       End With
    End If
 
 End Sub