Private Shared Sub ZipWriterExample()

      Dim zipFilePath As String = "D:\RealTimeZipExamples\MyZipFile.zip"

      ' NOTE: The trailing backslash is important, we use it below to build the paths in the zip archive

      Dim sourceFolder As String = "D:\ToZip\"



      ' Create a stream for a new zip file

      Using zipFileStream As New FileStream(zipFilePath, FileMode.Create, FileAccess.Write, FileShare.None)

'         Wrapping the ZipWriter object in a 'using' block will make sure the archive is closed

'         * properly after we're done adding content. If you use ZipWriter outside a 'using' block,

'         * make sure you call ZipWriter.CloseZipFile() to flush the archive's meta data

'         * to the output stream. 



        ' Create the ZipWriter object around the stream

        Using zipWriter As New ZipWriter(zipFileStream)

          Dim index As Integer

          Dim sourceFile As FileInfo

          Dim sourceFilenameInZip As String



'           As a convenience, ZipWriter offers the option to automatically close the output stream when

'             ZipWriter is closed. The behavior is disabled by default.

'         

'             In this example, we will not enable it because we are already closing the zip

'             file automatically in the 'using' block above. 

          'zipWriter.AllowOutputStreamClosure = true;



'           Since we'll be adding many files in the archive, we'll create a work buffer

'             ahead of time and use it over and over again to avoid creating a new buffer

'             each time we read from a source file. 

          Dim bufferSize As Integer = 64 * 1024

          Dim buffer(bufferSize - 1) As Byte



'           Create a local header object that will be used to specify the path/filename in

'             the zip file and other options like compression and encryption. 

          Dim localHeader As New ZipItemLocalHeader()



'           Options can be set "globally" before zipping starts.

'             We will set the file name for each file inside the loop. The other 

'             options have default values that satisfy us:

'             The compression method is Deflated at a the 'Normal' compression level

'             No encryption.

'             No comment. 

          'localHeader.CompressionMethod = CompressionMethod.Deflated;

          'localHeader.CompressionLevel = CompressionLevel.Normal;

          'localHeader.EncryptionMethod = EncryptionMethod.WinZipAes;

          'localHeader.EncryptionPassword = "password";



          ' Compute the index where the base path ends, minus the trailing backslash

          index = sourceFolder.Length - 1



          ' Go through all the files in the source folder and its sub-folders

          For Each sourcePath As String In Directory.EnumerateFiles(sourceFolder, "*", SearchOption.AllDirectories)

            ' Get file information

            sourceFile = New FileInfo(sourcePath)



            ' Compute a relative path for the file consisting of the full path minus the base path in 'sourceFolder'

            sourceFilenameInZip = sourcePath.Substring(index)



            ' Assign the filename in zip in the header

            localHeader.FileName = sourceFilenameInZip



            ' Optional. Set the last write date/time in the header

            localHeader.LastWriteDateTime = sourceFile.LastWriteTime



            Try

              ' Open the current file for sequential reading

              Using sourceFileStream As Stream = New FileStream(sourcePath, FileMode.Open, FileAccess.Read, FileShare.Read, bufferSize, FileOptions.SequentialScan)

'                 If we make it here, the source file has been opened successfully. We can

'                   safely add the item to the zip archive. 



                ' Write the local header for the file in the archive

                zipWriter.WriteItemLocalHeader(localHeader)



                ' Write the entire stream's content to the archive, using the work buffer we created

                zipWriter.WriteItemData(sourceFileStream, buffer, 0, bufferSize)

              End Using

            Catch e1 As FileNotFoundException

'               We're unable to open the source file. We will simply skip it and continue to

'                 the next one. 



            Catch e2 As System.Security.SecurityException

'               We're unable to open the source file. We will simply skip it and continue to

'                 the next one. 

            Catch e3 As DirectoryNotFoundException

'               We're unable to open the source file. We will simply skip it and continue to

'                 the next one. 

            Catch e4 As UnauthorizedAccessException

'               We're unable to open the source file. We will simply skip it and continue to

'                 the next one. 

            Catch e5 As PathTooLongException

'               We're unable to open the source file. We will simply skip it and continue to

'                 the next one. 

            End Try

          Next sourcePath

          

          ' OPTIONAL: A global comment for the zip archive can be set when closing the archive. By default, there is no comment.

          'Dim endHeader As New ZipEndHeader("Dynamically generated in <unknown> seconds")

          'zipWriter.CloseZipFile(endHeader)



          ' Because we are in a 'using' block, ZipWriter.Dispose() will take care of calling

          ' ZipWriter.CloseZipFile() for us if we don't do it here.



          '  When using ZipWrite outside of a 'using' block, ZipWriter.CloseZipFile() MUST be

          '  called explicitly or the zip file will be incomplete and unusable.

        End Using

      End Using

    End Sub

    Private Shared Function ZipWriterExampleXamarin() As Stream

'       NOTE: The zip file can be any type of stream you need. A network stream, a file stream, etc

'         The component will never call Stream.Seek() on the stream and will only write to it. 



      ' Create a writable stream for the zip file

      Dim zipFileStream As Stream = New MemoryStream()



'       Wrapping the ZipWriter object in a 'using' block will make sure the archive is closed

'         properly after we're done adding content. If you use ZipWriter outside a 'using' block,

'         make sure you call ZipWriter.CloseZipFile() to flush the archive's meta data

'         to the output stream. 



      ' Create the ZipWriter object around the stream

      Using zipWriter As New ZipWriter(zipFileStream)

'         As a convenience, ZipWriter offers the option to automatically close the output stream when

'           ZipWriter is closed. The behavior is disabled by default.

'         

'           In this example, we will not enable it as we want to manipulate the zip file

'           after it has been written. 

        'zipWriter.AllowOutputStreamClosure = true;



'         If we'll be adding many items in the archive, we'll create a work buffer

'           ahead of time and use it over and over again to avoid creating a new buffer

'           each time we read from a source file.

'          

'           This example doesn't add many items but still shows the technique. 

        Dim bufferSize As Integer = 64 * 1024

        Dim buffer(bufferSize - 1) As Byte



'         Create a local header object that will be used to specify the path/filename in

'           the zip file and other options like compression and encryption. 

        Dim localHeader As New ZipItemLocalHeader()



'         Options can be set "globally" before zipping starts.

'           We will set the file name for each file inside the loop. The other 

'           options have default values that satisfy us:

'           The compression method is Deflated at a the 'Normal' compression level

'           No encryption.

'           No comment. 

        'localHeader.CompressionMethod = CompressionMethod.Deflated;

        'localHeader.CompressionLevel = CompressionLevel.Normal;

        'localHeader.EncryptionMethod = EncryptionMethod.WinZipAes;

        'localHeader.EncryptionPassword = "password";



        ' Assign the filename in zip in the header

        localHeader.FileName = "MyFile1.dat"



        ' Optional. Set the last write date/time in the header

        localHeader.LastWriteDateTime = DateTime.Now



'         NOTE: The source data can be any type of stream you need. A network stream, a file stream, etc

'        The component will never call Stream.Seek() on the stream and will only read from it.

'       

'        This example will use memory data to keep it simple and on point. 



        ' Create some source data

        Dim dataToZip() As Byte = System.Text.Encoding.UTF8.GetBytes("The quick brown fox jumps over the lazy dog")



        ' Create a stream around the source data

        Using sourceDataStream As Stream = New MemoryStream(dataToZip, False)

          ' Write the local header for the file in the archive

          zipWriter.WriteItemLocalHeader(localHeader)



          ' Write the entire stream's content to the archive, using the work buffer we created

          zipWriter.WriteItemData(sourceDataStream, buffer, 0, bufferSize)

        End Using

      End Using



'       At this point, 'zipFileStream' contains a zip file. You can store it, upload it, etc as you

'         see fit. Because it is a stream, remember to change the current position to the start of the

'         stream if you wish to read the data. 



      zipFileStream.Seek(0, SeekOrigin.Begin)



      ' TODO: Send/store/whatever the zip file 



      Return zipFileStream

    End Function