If e.DataCol.Name = "接单日期" Then
    If e.DataRow.IsNull("接单日期") Then
        e.DataRow("订单编号") = Nothing
    Else
        Dim d As Date = e.DataRow("接单日期")
        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") \'生成订单编号的前6位,4位年,2位月.
        If e.DataRow("订单编号").StartsWith(bh) = False \'如果订单编号的前6位不符
            Dim max As String
            Dim idx As Integer

                        max = e.DataTable.Compute("Max(订单编号)","接单日期 >= #" & fd & "# And 接单日期 <= #" & ld & "#") \'取得该月的最大订单编号
            If max > "" Then \'如果存在最大订单编号
                idx = CInt(max.Substring(7,3)) + 1 \'获得最大订单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
            Dim s1 As String = "hh"
            e.DataRow("订单编号")= s1 & bh & "-" & Format(idx,"000")
        End If
    End If
End If

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