CustomOperationLogger.vb

Imports DevExpress.XtraPrinting
Imports DevExpress.XtraReports.Web.ClientControls
Imports DevExpress.XtraReports.Web.WebDocumentViewer
Imports System
Imports System.Drawing
Imports System.Drawing.Imaging
Imports System.IO
Imports System.Web

Namespace PowerPointExport

    Public Class CustomOperationLogger
        Inherits WebDocumentViewerOperationLogger

        Public Overrides Function ExportDocumentStarting(ByVal documentId As String, ByVal asyncExportOperationId As String, ByVal format As String, ByVal options As ExportOptions, ByVal printingSystem As PrintingSystemBase, ByVal doExportSynchronously As Func(Of ExportedDocument)) As ExportedDocument
            If Equals(format, "powerPoint") Then
                Return New ExportedDocument(ExportToPowerPoint(printingSystem, documentId), "application/vnd.ms-powerpoint", printingSystem.Document.Name & ".ppt")
            End If

            Return MyBase.ExportDocumentStarting(documentId, asyncExportOperationId, format, options, printingSystem, doExportSynchronously)
        End Function

        Private Function ExportToPowerPoint(ByVal printingSystem As PrintingSystemBase, ByVal documentId As String) As Byte()
            ' To the temp folder (for demo purposes)  
            Dim tempFolder = Hosting.HostingEnvironment.MapPath("~/App_Data/PowerPoint/")
            If Not Directory.Exists(tempFolder) Then
                Directory.CreateDirectory(tempFolder)
            End If

            ' image export options  
            Dim exportOptions As ImageExportOptions = New ImageExportOptions With {.ExportMode = ImageExportMode.SingleFilePageByPage, .Format = ImageFormat.Png, .PageBorderColor = Color.White, .Resolution = 600}
            ' PowerPoint Presentation  
            Dim size As Size = CalculateSize(printingSystem)
            Dim p As Presentation = New Presentation(size)
            ' go through each page  
            For i As Integer = 0 To printingSystem.Pages.Count - 1
                ' export image  
                Dim file = String.Format("{0}\{1}_{2}.png", tempFolder, documentId, i)
                exportOptions.PageRange =(i + 1).ToString()
                printingSystem.ExportToImage(file, exportOptions)
                ' add the image to the presentation  
                p.AddPage(file)
                ' clean up!  
                IO.File.Delete(file)
            Next

            ' save presentation  
            Dim resultFile As String = String.Format("{0}\{1}.ppt", tempFolder, documentId)
            p.SaveAs(resultFile)
            Dim document As Byte() = File.ReadAllBytes(resultFile)
            File.Delete(resultFile)
            Return document
        End Function

        Private Function CalculateSize(ByVal printingSystem As PrintingSystemBase) As Size
            Dim size As SizeF = printingSystem.Pages(0).PageSize.ToSize()
            Return GraphicsUnitConverter.Convert(size, GraphicsUnit.Document.ToDpi(), GraphicsUnit.Point.ToDpi()).ToSize()
        End Function
    End Class
End Namespace