Progress Event

Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.Forms.DocumentWriters

      
Public Sub DocumentWriterProgressExample()
   ' Get the input and output file names to use
   Dim inputFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Leadtools.docx")
   Dim outputFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Example.pdf")
   ' Show the progress dialog
   Using dlg As New MyProgressDialog(inputFileName, outputFileName)
      If dlg.ShowDialog() = DialogResult.OK Then
         MessageBox.Show("Done!")
      Else
         MessageBox.Show("User has canceled the operation or an error occured.")
      End If
   End Using
End Sub

' Dialog box to show the 
Private Class MyProgressDialog
   Inherits Form
   ' Files
   Private _inputFileName As String
   Private _outputFileName As String

   ' The controls on the dialog
   Private _descriptionLabel As Label
   Private _progressBar As ProgressBar
   Private _cancelButton As Button

   ' Has the operation been canceled?
   Private _isCancelPending As Boolean
   ' Is the dialog working?
   Private _isWorking As Boolean

   Public Sub New(inputFileName As String, outputFileName As String)
      InitializeComponent()

      _inputFileName = inputFileName
      _outputFileName = outputFileName
      _isCancelPending = False
      _isWorking = True
   End Sub

   Protected Overrides Sub OnLoad(ByVal e As EventArgs)
      ' To keep the UI functioning, do the conversion in a separate thread
      BeginInvoke(New MethodInvoker(AddressOf DoWork))

      MyBase.OnLoad(e)
   End Sub

   Private Sub DoWork()
      Dim docWriter As DocumentWriter
      Dim operation As String = String.Empty

      Dim progressHandler As EventHandler(Of DocumentProgressEventArgs) = _
         Sub(sender As Object, e As DocumentProgressEventArgs)
            ' Update the description label progress bar
            _descriptionLabel.Text = operation
            _progressBar.Value = e.Percentage

            ' Check if the user clicked the Cancel button, if so, abort the operation
            If (_isCancelPending) Then
               e.Cancel = True
            End If

            Application.DoEvents()
         End Sub

      ' Get the number of pages
      Dim codecs As New RasterCodecs()
      codecs.Options.RasterizeDocument.Load.Resolution = 300
      Dim pageCount As Integer = codecs.GetTotalPages(_inputFileName)

      ' Create the document writer
      docWriter = New DocumentWriter()

      ' Create the document
      operation = "Creating the document..."

      ' Subscribe to the progress event
      AddHandler docWriter.Progress, progressHandler
      docWriter.BeginDocument(_outputFileName, DocumentFormat.Pdf)

      ' Add the pages
      For pageNumber As Integer = 1 To pageCount

         If _isCancelPending Then
            Exit For
         End If

         ' Load the page as SVG
         Dim page As New DocumentSvgPage()
         page.SvgDocument = codecs.LoadSvg(_inputFileName, pageNumber, Nothing)

         ' Add the page, notice we will not be using image/text feature (the default)
         operation = String.Format("Adding page {0} of {1}...", pageNumber, pageCount)
         docWriter.AddPage(page)

         ' Delete the SVG
         page.SvgDocument.Dispose()
      Next

      ' Finally finish writing the PDF file on disk
      operation = "Finishing the document..."
      docWriter.EndDocument()

      ' Remove the progress handler
      RemoveHandler docWriter.Progress, progressHandler

      codecs.Dispose()

      ' Set the dialog results based on whether the user has canceled the operation
      If _isCancelPending Then
         DialogResult = DialogResult.Cancel
      Else
         DialogResult = DialogResult.OK
      End If

      ' The dialog can be closed now
      _isWorking = False

      ' We are done
      Close()
   End Sub

   Private Sub _cancelButton_Click(sender As Object, e As EventArgs)
      ' Set the isCanceled variable to true, this will break from the
      ' progress callback and closes the dialog
      _isCancelPending = True
   End Sub

   Protected Overrides Sub OnFormClosing(ByVal e As FormClosingEventArgs)
      ' Dont allow the form to close while the callback is still working
      ' Instead, cancel the operation
      If _isWorking Then
         e.Cancel = True
      End If

      MyBase.OnFormClosing(e)
   End Sub

   Private Sub InitializeComponent()
      ' Create the controls in this form, a text label, a progress bar and a cancel button
      SuspendLayout()

      ' Text label
      _descriptionLabel = New Label()
      _descriptionLabel.Location = New Point(26, 21)
      _descriptionLabel.Name = "_descriptionLabel"
      _descriptionLabel.Size = New Size(367, 23)
      _descriptionLabel.TabIndex = 0
      _descriptionLabel.TextAlign = ContentAlignment.MiddleLeft
      _descriptionLabel.Text = "Creating final document..."

      ' Progress bar
      _progressBar = New ProgressBar()
      _progressBar.Location = New Point(27, 47)
      _progressBar.Name = "_progressBar"
      _progressBar.Size = New Size(364, 23)
      _progressBar.TabIndex = 1

      ' Cancel button
      _cancelButton = New Button()
      _cancelButton.DialogResult = DialogResult.Cancel
      _cancelButton.Location = New Point(172, 76)
      _cancelButton.Name = "_cancelButton"
      _cancelButton.Size = New Size(75, 23)
      _cancelButton.TabIndex = 2
      _cancelButton.Text = "Cancel"
      _cancelButton.UseVisualStyleBackColor = True
      AddHandler _cancelButton.Click, AddressOf _cancelButton_Click

      ' Add the controls
      Controls.Add(_descriptionLabel)
      Controls.Add(_progressBar)
      Controls.Add(_cancelButton)

      ' Initialize the dialog
      AutoScaleDimensions = New SizeF(6.0F, 13.0F)
      AutoScaleMode = AutoScaleMode.Font
      CancelButton = _cancelButton
      ClientSize = New Size(420, 118)
      FormBorderStyle = FormBorderStyle.FixedDialog
      MaximizeBox = False
      MinimizeBox = False
      Name = "MyProgressDialog"
      ShowInTaskbar = False
      StartPosition = FormStartPosition.CenterParent
      Text = "DocumentWriter Progress Example"

      ResumeLayout()
   End Sub
End Class