表A,DataColChanged事件
Select Case e.DataCol.Name
Case "编号"
If e.NewValue > "" Then
Dim d As Date = new Date()
Dim ns() As String = {"表B","表C","表D"}
For Each n As String In ns
Dim d1 As Date = DataTables(n).Compute("Max(日期)","[编号] = '" & e.NewValue & "'")
If d1 > d Then d = d1
Next
dr("末次订购日期") = d
End If
End Select