If e.DataCol.Name = "下单时间" Then
If e.DataRow.IsNull("下单时间") Then
e.DataRow("流水号") = Nothing
Else
Dim d As Date = e.DataRow("下单时间")
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("流水号").StartsWith(bh) = False '如果编号的前6位不符
Dim max As String
Dim idx As Integer
max = e.DataTable.sqlCompute("Max(流水号)","下单时间>= #" & fd & "# And 下单时间 < #" & ld.adddays(1) & "# And [_Identify] <> " & e.DataRow("_Identify")) '取得该月的最大编号
If max > "" Then '如果存在最大编号
idx = CInt(max.Substring(7,4)) + 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("流水号") = bh & "-" & Format(idx,"0000")
e.DataRow.save
End If
End If
End If