我想大家一定會遇到要把資料匯出成 Excel 的需求. 以現有的工具, 大家想到作法大概都是先把資料放到一個 datatable 之中, 後叫用 UW.ExcelPOI.DTToExcelAndWriteToClient 就結束了.

前兩天遇到一個需求, 輸出的 Excel 要加上表頭, 如下圖



於是乎把  UW.ExcelPOI.DTToExcelAndWriteToClient 做了一些擴充, (其實應該說是幫 DTToWorkSheet 做了擴充), 過程如下.

1. 需求: 一個可以快速填入欄位的 Sub (method or function)
A. 每一個 Cell 可以設定內容(文字), 字型大小, 跨欄數, 對齊方式. (其它的未來再來擴充, 例如顔色).
B. 每一個 Row 由 Cell 組成, 由左到右.
C. 一次可以填多個 Row

2. 實作:
A. 先定義 Cell

    Public Class Cell

        Public Content As String

        Public Colspan As Int32 = 1

        Public Alignment As NPOI.SS.UserModel.HorizontalAlignment

        Public FontHeightInPoints As Int32 = 0



        Sub New(Content As String, Optional Colspan As Int32 = 1,

                Optional Alignment As NPOI.SS.UserModel.HorizontalAlignment = NPOI.SS.UserModel.HorizontalAlignment.General,

                Optional FontHeightInPoints As Int32 = 0)

            Me.Content = Content

            Me.Colspan = Colspan

            Me.Alignment = Alignment

            Me.FontHeightInPoints = FontHeightInPoints

        End Sub

    End Class

B. Row 的格式: 我想最直的覺的就是 List(of Cell) 了吧.

C. 多個 Row 的表示法: List(Of List(Of Cell))

D. 來把 Cell 填入 WorkSheet  吧, 

Public Shared Sub AddRows(WS As HSSFSheet, ltRows As List(Of List(Of Cell)), ByRef StartRow As Int32)

共有三個參數: WS  和 ltRows 應該不用解釋了. 最後一個 StartRow 用來指定插入資料的開始 Row.

E.  完整程式碼: (程式碼不看沒關係, 但要跳到 F. 重點講解哦)

Public Shared Sub AddRows(WS As HSSFSheet, ltRows As List(Of List(Of Cell)), ByRef StartRow As Int32)

        Dim WR As HSSFRow

        If ltRows IsNot Nothing Then

            For Each ltRow As List(Of Cell) In ltRows

                WR = WS.CreateRow(StartRow)

                Dim C As Int32 = 0

                For Each cell As Cell In ltRow

                    Dim ic As NPOI.SS.UserModel.ICell = WR.CreateCell(C)

                    ic.SetCellValue(cell.Content)



                    Dim cs As NPOI.SS.UserModel.ICellStyle = WS.Workbook.CreateCellStyle()

                    cs.Alignment = cell.Alignment

                    If cell.FontHeightInPoints > 0 Then

                        Dim oFont As NPOI.SS.UserModel.IFont = WS.Workbook.CreateFont()

                        oFont.FontHeightInPoints = cell.FontHeightInPoints

                        cs.SetFont(oFont)

                    End If



                    ic.CellStyle = cs



                    If cell.Colspan > 1 Then

                        WS.AddMergedRegion(New CellRangeAddress(StartRow, StartRow, C, C + cell.Colspan - 1))

                        C += cell.Colspan - 1

                    End If

                    C += 1

                Next



                StartRow += 1

            Next

        End If

    End Sub

F. 重點講解:
這個 function 在實作時有兩個卡點:
1. 如何合併欄: 

WS.AddMergedRegion(New CellRangeAddress(StartRow, StartRow, C, C + cell.Colspan - 1))

2. 如何設定字型大小和對齊方式:

                    Dim cs As NPOI.SS.UserModel.ICellStyle = WS.Workbook.CreateCellStyle()

                    cs.Alignment = cell.Alignment

                    If cell.FontHeightInPoints > 0 Then

                        Dim oFont As NPOI.SS.UserModel.IFont = WS.Workbook.CreateFont()

                        oFont.FontHeightInPoints = cell.FontHeightInPoints

                        cs.SetFont(oFont)

                    End If



                    ic.CellStyle = cs

這裡有件有有趣的事, 我一開始是這樣寫的.

ic.CellStyle.Alignment = cell.Alignment

結果是整個 WorkSheet 的對齊方式都被改了. 我猜當 WorkSheet 初建立時, CellStyle 都是用同一個. 所以改任一個 cell 的 CellStyle 會同時改到所有 cell 的.

G. 使用方式:

        Dim ltHeader As New List(Of List(Of UW.ExcelPOI.Cell))

        Dim ltLine As New List(Of UW.ExcelPOI.Cell)

        ltLine.Add(New UW.ExcelPOI.Cell(DB.SysConfig.SYSTEM_NAME & "應收明細表", 16,

                                        NPOI.SS.UserModel.HorizontalAlignment.Center, 28))

        ltHeader.Add(ltLine)



        '第二行

        ltLine = New List(Of UW.ExcelPOI.Cell)

        ltLine.Add(New UW.ExcelPOI.Cell("期間: " & Me.txtbl_date_s.Text & " ~ " & Me.txtbl_date_e.Text, 10,

                                        NPOI.SS.UserModel.HorizontalAlignment.Left, 20))

        ltLine.Add(New UW.ExcelPOI.Cell("製表日期: " & Now.ToString("yyyy-MM-dd"), 6,

                                        NPOI.SS.UserModel.HorizontalAlignment.Right, 20))

        ltHeader.Add(ltLine)



        UW.ExcelPOI.DTToExcelAndWriteToClient(newdt, ltHeader:=ltHeader)

IsDefaultNewVersion 設為 true 時, 要改用 { } 來標記變數.

在 Application_BeginRequest 可以加入 BlockHacker

    void Application_BeginRequest(object sender, EventArgs e)

    {

        UW.WU.BlockHacker();

    }

可以做一些基本的防駭.

在 Sys_Coonfig 中有兩個參數要設定: WEB_ERROR_ExceptionCountBeforeBlock, WEB_ERROR_ExceptionCountingIntervalInMinutes

另外還有一個參數: WEB_ERROR_DangerousKeywords, 內容請用逗號分隔, 若是發生 Exception 時, Form 或 QueryString 中含有指定的文字, 收到的警告信會標示為高重要性.