老师请帮我看下代码，为什么不能自己增加顺序好，都是001

Select e.DataCol.Name
    Case "拜访_类型","拜访_人员"
        If e.DataRow.IsNull("拜访_类型") OrElse e.DataRow.IsNull("拜访_人员") Then
            e.DataRow("编号") = Nothing
        Else
            Dim bfry As String = e.DataRow("拜访_人员")
            If e.DataRow("拜访_人员") = "汪晓光" Then
                bfry = "W"
            ElseIf e.DataRow("拜访_人员") = "张志斌" Then
                bfry = "B"
            ElseIf e.DataRow("拜访_人员") = "巩中桂" Then
                bfry = "G"
            ElseIf e.DataRow("拜访_人员") = "汪振学" Then
                bfry = "X"
            ElseIf e.DataRow("拜访_人员") = "周荣凯" Then
                bfry = "Z"
            ElseIf e.DataRow("拜访_人员") = "张良斌" Then
                bfry = "L"
            ElseIf e.DataRow("拜访_人员") = "吴小龙" Then
                bfry = "I"
            ElseIf e.DataRow("拜访_人员") = "刘杰" Then
                bfry = "J"
            Else
                bfry = "P"
            End If
           
            Dim bflx As String = e.DataRow("拜访_类型")
            If e.DataRow("拜访_类型") = "电话" Then
                bflx = "D"
            Else
                bflx = "Z"
            End If
           
            Dim bf As String = "BF"
            Dim d As Date = e.DataRow("拜访_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 = bf & Format(d,"yyMM") \'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)","拜访_日期 >= #" & fd & "# And 拜访_日期 <= #" & ld & "# And [序号] <> " & e.DataRow("序号")) \'取得该月的最大编号
                If len(max) = 14 Then   \'如果存在最大编号
                    idx = CInt(max.Substring(11,3)) + 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 & bflx & bfry & "-" & Format(idx,"000")
            End If
        End If
End Select

结果不一样啊

每次的调试结果都是一样的

到003后又不增加了