主题：[求助]子表计算

可以写到子表的datacolchanged事件

If e.DataCol.name = "日期" Then
    Dim pr As DataRow = e.DataRow.GetParentRow("父表")
    If pr IsNot Nothing Then
        Dim crs As List(of DataRow) = pr.GetChildRows("子表")
        Dim cnt As Integer
        Dim maxDate As Date
        For Each cr As DataRow In crs
            If cr.IsNull("日期") Then
                Exit For
            End If
            If maxDate < cr("日期") Then maxDate = cr("日期")
            cnt = cnt + 1
           
        Next
        If crs.Count = cnt Then
            pr("日期") = maxDate
        Else
            pr("日期") = Nothing
        End If
    End If
End If