• How to Use HTML5 File Drag & Drop
• How to Open Dropped Files Using HTML5 and JavaScript
• How to Asynchronously Upload Files Using HTML5 and Ajax
• How to Create File Upload Progress Bars in HTML5 and JavaScript

這幾篇文章提到使用拖拉方式將檔案放到網頁裡面
然後在本地端預覽，然後ajax上傳，上傳時還有 progress bar
一整套運作模式說明，並附上sample code，挺棒的
附檔sample code

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測試後補充:
1. 範例中的 dragover event 要改成 dragenter 比較正確
然後 dragover 最好是做成 return false (ev.stopPropagation())
2. Server端不能用Requst.Files收檔案，要直接處理 Request.InputStream另存成檔案

 

主要是使用 Printing.PreviewPrintController 的產生預覽圖片的功能來儲存列印內容, 再把圖片送到印表機, 以保証列印內容和儲存的圖檔是一致的. 值得一提的是, 在預覽時可以使用不同的印表機, 以便讓產生較小的圖檔, 否則有時會發生 GDI+ 的錯誤.

Sample 如下:

Imports System.Drawing.Printing

Namespace X

    Partial Public Class PrintSomething

        Dim PD As PrintDocument

        Dim ppc As New Printing.PreviewPrintController()

        Dim TotalPage As Int32 = 0

        ''' <summary>

        ''' 第幾次列印, 用來控制寫出的圖檔

        ''' </summary>

        ''' <remarks></remarks>

        Dim PrintCount As Int32 = 1

        Dim PageCount As Int32 = 1

            :

            :

            :

      

        Sub New(ByVal oPM As DB.PackingListMain, ByVal dtDetail As DataTable, dtUsedCoupon As DataTable)

            '初始化資料

            :

            :

            :

        End Sub

        Sub InitPrintDocument()

            '在這裡設定 PrintDocument 的紙張, 印表機, 邊界, 橫印或直印

            PD = New PrintDocument

            :

            :

            :

        End Sub

        Sub print()

            InitPrintDocument()

            PD.PrintController = ppc

           

            ' 第一次先把列印結果存在 Printing.PreviewPrintController 中

            AddHandler PD.PrintPage, AddressOf GeneratePreview

            '再來儲存圖片

            AddHandler PD.EndPrint, AddressOf SaveImage

            PD.Print()

        End Sub



        Dim ppi() As Printing.PreviewPageInfo

        Dim PrintPage As Int32 = 0

        Sub SaveImage(ByVal sender As Object, ByVal ev As PrintEventArgs)

            PrintDebug("Save Image Start, " & Now.ToString("yyyy-MM-dd HH:mm:ss.fff"))

            '把圖檔存起來

            Dim TF As String = Now.ToString("yyyyMMddHHmmss") ' DB.SysConfig.Path.LocalDataRoot

            Dim PathLocal As String = "C:\PrintLog\" & TF.Substring(0, 4) & "-" & TF.Substring(4, 2) & "\"

            Dim PathPackingListSheetImage As String = DB.SysConfig.PackingListSheetImage & TF.Substring(0, 4) & "-" & TF.Substring(4, 2) & "\"

            System.IO.Directory.CreateDirectory(PathLocal)

            System.IO.Directory.CreateDirectory(PathPackingListSheetImage)

            Dim LatestImages As String = ""

            ppi = ppc.GetPreviewPageInfo()

            For x As Integer = 0 To ppi.Length - 1

                Dim Filename As String = TF & "_" & Me.oPM.Id & "_" & x & ".png"

                ppi(x).Image.Save(PathLocal & Filename, System.Drawing.Imaging.ImageFormat.Png)

            Next



            '把圖檔印出來

            For x As Integer = 0 To ppi.Length - 1

  '建立新的 PrintDocument

                InitPrintDocument()

                If CST.WebConfig.Server_NAME = "測試主機" Then

                    UW.WU.DebugWriteLine("PrinterName: " & Me.PD.PrinterSettings.PrinterName)

                    UW.WU.DebugWriteLine("PaperSize: " & PD.DefaultPageSettings.PaperSize.PaperName)

                    PD.DocumentName = "PackingList"

                    PD.PrinterSettings.PrintFileName = "C:\PDF\PackingList" & Now.ToString("yyyyMMddHHmmss") & "_" & PrintPage & ".prn"

                    PD.PrinterSettings.PrintToFile = True

                    'PD.PrinterSettings.

                End If

                '很奇怪, 這裡不會分頁, 所以要一張一張印   

                AddHandler PD.PrintPage, AddressOf pd_PrintPage2

                PD.Print()



               PrintPage += 1

            Next

        End Sub

        Private Sub pd_PrintPage2(ByVal sender As Object, ByVal ev As PrintPageEventArgs)

            '很奇怪, 這裡不會分頁, 所以要一張一張印           

            ev.Graphics.DrawImage(ppi(PrintPage).Image, 0, 0)

            ev.HasMorePages = False

        End Sub



        Private Sub GeneratePreview(ByVal sender As Object, ByVal ev As PrintPageEventArgs)

            ' 列印內容

        End Sub

        End Class

    End Class

End Namespace