Dim dt1 As DataTable
dt1 = FrmMain.DSExkursionsdaten.Firma.Copy
dt1.Columns.Add("ExDatum", GetType(DateTime))
 
dvx = New DataView(FrmMain.DSExkursionsdaten.Bewertung)
dvx.RowFilter = "Datum > '" & FrmMain.Txt1Kr1.Text & "' AND Datum < '" & _
  FrmMain.Txt2Kr1.Text & "'"
 
For Each row As DataRow In FrmMain.DSExkursionsdaten.Bewertung.Rows
 
     dt1.Rows(row.Item("IDFirma")).Item("ExDatum") = dvx.Item(row.Item( _
       "IDFirma")).Item("Datum")
 
Next
 
dv1 = New DataView(dt1)
dv1.RowFilter = "ExDatum IS NOT NULL"
 
FrmMain.LstListe.DataSource = dv1.ToTable