我想在编号之前加上固定的文字，比如说ZSDD，应该怎么加呢

If e.DataCol.Name =  "日期" Then
    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