Zip with Progress Monitoring Event Callbacks

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This VB.NET example program provides documentation on all the event callback functionality that exists when writing a Zip archive.

    ' When using events, we must declare the variable as a global or
    ' class member WithEvents
    ' Once it is declared, we can select the "zip" object from 
    ' the VB.NET IDE to see the events.  If you select the event
    ' from the dropdown, Visual Studio will create the callback
    ' subroutine for you.
    Dim WithEvents zip As New Chilkat.Zip()

    ' Zip with progress monitoring callback events.
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        ' These two lines can be called once at the beginning of your program.
        zip.UnlockComponent("Anything for 30-day trial")
        ' Don't forget to enable events.
        ' Don't forget to enable events.
        ' Don't forget to enable events.
        ' Don't forget to enable events.
        ' Don't forget to enable events.
        ' Don't forget to enable events.
        ' Don't forget to enable events.
        ' Don't forget to enable events.
        ' Don't forget to enable events.
        ' Don't forget to enable events.
        ' Don't forget to enable events.
        zip.EnableEvents = True

        ' Initialize our Zip object.
        zip.NewZip("myZip.zip")

        ' Add some files.
        Dim success As Boolean
        Dim recurseDirectories As Boolean
        Dim saveExtraPath As Boolean
        Dim archiveOnly As Boolean
        Dim includeHidden As Boolean
        Dim includeSystem As Boolean
        recurseDirectories = True
        saveExtraPath = False
        archiveOnly = False
        includeHidden = True
        includeSystem = True
        ' When SaveExtraPath is false, we will create a zip containing
        ' relative directory paths.  In this case, the zip is created as if
        ' our current working directory was "c:/temp/a".
        success = zip.AppendFilesEx("c:/temp/a/*", recurseDirectories, saveExtraPath, archiveOnly, includeHidden, includeSystem)
        If (Not success) Then
            MessageBox.Show(zip.LastErrorText)
            Exit Sub
        End If

        ' Writes "myZip.zip", which is the filename specified
        ' in the NewZip method.
        ' We could change the filename by setting the Filename property:
        ' zip.FileName = "somethingElse.zip"
        '
        ' The callback methods are located in the subroutines below.
        success = zip.WriteZipAndClose()
        If (Not success) Then
            MessageBox.Show(zip.LastErrorText)
            Exit Sub
        End If

        MessageBox.Show("Zip successful!")

    End Sub

    ' Callback to monitor the percentage progress completion of zipping.
    ' The zip operation can be aborted by setting the args.Abort property = true prior to returning.
    Private Sub zip_OnWriteZipPercentDone(ByVal sender As Object, ByVal args As Chilkat.WriteZipPercentDoneEventArgs) Handles zip.OnWriteZipPercentDone
        ' args.PercentDone contains an integer value ranging from 1 to 100.
        ProgressBar1.Value = args.PercentDone

        ' If we want to abort the zipping at any point, simply set args.Abort = true:
        ' If we uncomment the following lines, the zipping will be aborted once
        ' it is 50% complete:
        'If (args.PercentDone >= 50) Then
        'args.Abort = True
        'End If

    End Sub

    ' When creating large Zips, there may be a long time between percent-done callbacks.
    ' The OnAbortCheck callback is called about once every .5 seconds that elapse without
    ' a OnWriteZipPercentDone callback.
    Private Sub zip_OnAbortCheck(ByVal sender As Object, ByVal args As Chilkat.AbortCheckEventArgs) Handles zip.OnAbortCheck
        ' To abort the zipping, set args.Abort = true:
        ' if (....) then
        '      args.Abort = True
        ' end if
    End Sub

    ' The OnFileZipped callback is called for each file successfully appended to the zip.
    Private Sub zip_OnFileZipped(ByVal sender As Object, ByVal args As Chilkat.FileZippedEventArgs) Handles zip.OnFileZipped
        ' args contains four members:
        ' args.Abort: You may set this to true to abort the zipping process.
        ' args.CompressedSize: The compressed size in bytes.
        ' args.FileSize: The original uncompressed size of the file.
        ' args.FileName: The filename as it will appear in the Zip.
        ListBox2.Items.Add(args.FileName)
    End Sub

    ' The OnToBeZipped event callback is called during the zip creation process, once for
    ' each file just before it is to be added to the zip.  The application has the opportunity
    ' to exclude files by setting args.Exclude = True.
    Private Sub zip_OnToBeZipped(ByVal sender As Object, ByVal args As Chilkat.ToBeZippedEventArgs) Handles zip.OnToBeZipped
        ' args contains three members:
        ' args.Exclude: You may set this to true to exclude the file from the zip.
        ' args.FileSize: The original uncompressed size of the file.
        ' args.FileName: The filename (including path) to be added.
    End Sub

    ' This callback is called once at the beginning of the zip creation process.
    Private Sub zip_OnWriteZipBegin(ByVal sender As Object, ByVal args As System.EventArgs) Handles zip.OnWriteZipBegin
        ' args contains no information...
    End Sub

    ' This callback is called once at the end of the zip creation process.
    Private Sub zip_OnWriteZipEnd(ByVal sender As Object, ByVal args As System.EventArgs) Handles zip.OnWriteZipEnd
        ' args contains no information...
    End Sub