主题：有关自动编号的问题

改成这样就可以了

Dim drs As List (of DataRow)
drs = DataTables("表A").Select("[内容] Is null")
If drs IsNot Nothing Then
    Dim n As Integer = drs.count
  If n>0 Then
        For Each dr As DataRow In drs
            dr.Delete()
        Next
End If

Else

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 & "# 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(7,3)) + 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