If e.DataCol.Name = "日期" Then
If e.DataRow.IsNull("日期") Then
e.DataRow("编号") = Nothing
Else
Dim d As Date = e.DataRow("日期")
Dim y As Integer = d.Year
Dim m As Integer = d.Month
Dim Days As Integer = Date.DaysInMonth(y,m)
Dim fd As Date = New Date(y,m,1) \'获得该月的第一天
Dim ld As Date = New Date(y,m,Days) \'获得该月的最后一天
Dim bh As String = Format(d,"yyyyMM") \'生成编号的前6位,4位年,2位月.
If e.DataRow("编号").StartsWith(bh) = False \'如果编号的前6位不符
Dim max As String
Dim idx As Integer
max = e.DataTable.Compute("Max(编号)","日期 >= #" & fd & "# And 日期 <= #" & ld & "#") \'取得该月的最大编号
If max > "" Then \'如果存在最大编号
idx = CInt(max.Substring(7,3)) + 1 \'获得最大编号的后三位顺序号,并加1
Else
idx = 1 \'否则顺序号等于1
End If
e.DataRow("编号") = bh & "-" & Format(idx,"000")
End If
End If
End If

看看这个帖子：

http://www.foxtable.com/bbs/dispbbs.asp?BoardID=2&ID=29605&skin=0