If e.DataCol.Name = "日期" Then
If e.DataRow.IsNull("日期") Then
e.DataRow("第几周") = Nothing
Else
Dim calCommon As New System.Globalization.GregorianCalendar()
Dim dt As Date = e.DataRow("日期")
e.DataRow("第几周") = calCommon.GetWeekOfYear(dt, System.Globalization.CalendarWeekRule.FirstDay, 0)
End If
End If