[VB.NET]: Errore di concorrenza durante l'UPDATE

[bubu80]

ciao a tutti

ERRORE:
"Violazione di concorrenza: UpdateCommand ha modificato 0 record."

nn riesco a capire dove sbaglio

  Dim cmd As SqlCommand = New SqlCommand("SELECT * FROM TAB1", con)
  Dim cmdUp as new SqlCommand 
  cmdUP.Connection = con
  cmdUp.CommandText = "UPDATE TAB1 SET campo1=@cp1,ora=GETDATE() WHERE campo2='@cp2' "

        cmdUp.Parameters.Add(New SqlParameter("@cp1", SqlDbType.Int, 2, ParameterDirection.Input, False, 0, 0, "campo1", DataRowVersion.Current, Nothing))
        cmdUp.Parameters.Add(New SqlParameter("@cp2", SqlDbType.NVarChar, 50, ParameterDirection.Input, False, 0, 0, "campo2", DataRowVersion.Original, Nothing))

    Dim daS = New SqlDataAdapter(cmd)
    daS.UpdateCommand = cmdUP
    
    daS.Fill(dtTest)
   
    'compie le varie modifiche sul mio datatable
    '....

    Try
         daS.Update(dtTest)
     Catch ex as Exception  
         Console.WriteLine(ex.Message)
     End Try