主题：[求助]怎样用表达式计算周

要写代码，在datacolchanged事件写代码

If e.DataCol.name = "日期" Then
    If e.NewValue = Nothing Then
        e.DataRow("第一列") = Nothing
    Else
        Dim gc As System.Globalization.GregorianCalendar = new System.Globalization.GregorianCalendar()
        Dim weekOfYear As Integer = gc.GetWeekOfYear(e.newvalue,System.Globalization.CalendarWeekRule.FirstDay, DayOfWeek.Monday)
        e.DataRow("第一列") = weekOfYear
    End If
End If