主题：关于自动编号的问题

参考下

流水号,以DH-年统计单据
If e.DataCol.Name = "订货日期" Then
    If e.DataRow.IsNull("订货日期") Then
        e.DataRow("流水号") = Nothing
    Else
        Dim d As Date = e.DataRow("订货日期")
        Dim y As Integer = d.Year
        Dim fd As Date = New Date(y,1,1) '获得该年的第一天
        Dim ld As Date =  new Date(y,12,31) '获得该年的最后一天
        Dim bh As String = "DH-" & Format(d,"yyyy") '生成编号的前4位,4位年.
        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.Compute("Max(流水号)","订货日期 >= #" & fd & "# And 订货日期 <= #" & ld & "# And [_Identify] <> " & e.DataRow("_Identify")) '取得该年的最大编号
            If max > "" Then '如果存在最大编号
                idx = CInt(max.Substring(8,4)) + 1 '获得最大编号的后三位顺序号,并加1,DH-201701-XXX
            Else
                idx = 1 '否则顺序号等于1
            End If
            e.DataRow("流水号") =  bh & "-" & Format(idx,"0000")
        End If
    End If
End If