Dynamic file manipulation

Dynamic file manipulation

• cosmopoet

  How about the following

  Dim FirstTwoLetters as string = "MS"

  
  For Each foundFile As String In My.Computer.FileSystem.GetFiles _
  ("C:\test")
  If foundFile.substring = FirstTwoLetters then

  ...Process the file with first two letter match

  End If
  Next
  

  As far as the process of unzipping them goes - you could try shelling the zip file.

  http://www.vb-helper.com/howto_shell_zip_and_unzip.html

  Provides a simple way but there are numerous other zip components out there to use.

  A simple web search on WB.NET + zip will reveal a lot of links with components etc.

  
  

• zagolin

   

  The is a Microsoft example that uses the java libraries to handle the zip files.  http://msdn.microsoft.com/msdnmag/issues/03/06/ZipCompression/default.aspx

  I have been trying to convert the code to VB. I keep get an invalid cast exception on the following line.  Any help would be greatly appreceated.

  'Reset to first object in collection.  Here is where I get the invalid cast exception

  m_Wrapped = m_Method

  Here is the main form

  Imports System

  Imports System.Collections

  'Imports java.util

  Imports java.util.zip

  'Imports CsZip

  Imports System.Collections.Specialized

  Imports System.IO

  Imports System.ComponentModel

  Imports System.Reflection

  Public Class Form1

  Private m_CurrentFile As java.util.zip.ZipFile

  Public Property CurrentFile() As ZipFile

  Get

  Return m_CurrentFile

  End Get

  Set(ByVal value As ZipFile)

  Try

  m_CurrentFile.close()

  Catch ex As Exception

  End Try

  m_CurrentFile = value

  If m_CurrentFile.ToString <> "" Then

  DisplayEntries()

  Text = m_CurrentFile.getName

  End If

  End Set

  End Property

  Private Sub DisplayEntries()

  zipListView.BeginUpdate()

  zipImageList.Images.Clear()

  zipListView.Items.Clear()

  Dim imgs As New ListDictionary

  Dim entry As ZipEntry

  For Each entry In New CsZip.EnumerationAdapter(New CsZip.EnumerationMethod(AddressOf CurrentFile.entries))

  If Not entry.isDirectory Then

  'Try

  Dim name As String = entry.getName

  Dim item As New ListViewItem(Path.GetFileName(name))

  item.SubItems.Add(entry.getSize.ToString)

  item.SubItems.Add(entry.getCompressedSize.ToString)

  item.SubItems.Add(Path.GetDirectoryName(name))

  item.Tag = entry

  Dim ext As String = Path.GetExtension(name)

  If imgs(ext) = Nothing Then

  Dim ic As Icon = IconFromFileType(name)

  If ic.ToString <> "" Then

  zipImageList.Images.Add(ic)

  imgs(ext) = zipImageList.Images.Count - 1

  End If

  If imgs(ext).ToString <> "" Then

  item.ImageIndex = imgs(ext)

  End If

  zipListView.Items.Add(item)

  End If

  'Catch ex As Exception

  'End Try

  End If

  Next

  zipListView.EndUpdate()

  End Sub

  The class that does the zip file handleing

  Imports System

  Imports System.Collections

  Imports java.util

  Imports java.util.zip

  Imports System.Collections.Specialized

  Namespace frmZip

  Public Delegate Function EnumerationMethod() As Enumeration

  Public Class EnumerationAdapter

  Implements IEnumerable

  Private m_Method As EnumerationMethod

  Public Class EnumerationWrapper

  Implements IEnumerator

  Private m_Method As EnumerationMethod

  Private m_Wrapped As Enumeration

  Private m_Current As Object

  Public Sub New(ByRef method As EnumerationMethod)

  m_Method = method

  End Sub

  Public ReadOnly Property Current() As Object Implements System.Collections.IEnumerator.Current

  Get

  Return m_Current

  End Get

  End Property

  Public Sub Reset() Implements System.Collections.IEnumerator.Reset

  ' Reset to first object in collection.

  If m_Method Is Nothing Then Throw New InvalidOperationException

  Try

  'Reset to first object in collection.  Here is where I get the invalid cast exception

  m_Wrapped = m_Method

  If m_Wrapped Is Nothing Then Throw New InvalidOperationException

  Catch ex As Exception

  MessageBox.Show(ex.Message.ToString)

  End Try

   

  End Sub

  Public Function MoveNext() As Boolean Implements System.Collections.IEnumerator.MoveNext

  If m_Wrapped Is Nothing Then Reset()

  Dim Result As Boolean = m_Wrapped.hasMoreElements

  If Result Then m_Current = m_Wrapped.nextElement

  Return Result

  End Function

  End Class

  Public Sub New(ByRef method As EnumerationMethod)

  If method Is Nothing Then Throw New ArgumentException

  m_Method = method

  End Sub

  Public Function GetEnumerator() As System.Collections.IEnumerator Implements System.Collections.IEnumerable.GetEnumerator

  Return New EnumerationWrapper(m_Method)

  End Function

  End Class

  Public Delegate Function FilterEntryMethod(ByRef e As ZipEntry) As Boolean

  Public Class ZipUtils

  Public Shared Sub CopyStream(ByVal from As java.io.InputStream, ByVal [to] As java.io.OutputStream)

  Dim buffer(8192) As SByte

  buffer(8192) = New SByte

  Dim got As Integer

  While (got = from.read(buffer, 0, buffer.Length)) > 0

  [to].write(buffer, 0, got)

  End While

  End Sub

  Public Shared Sub ExtractZipFile(ByVal file As ZipFile, ByVal path As String, ByVal filter As FilterEntryMethod)

  Dim entry As ZipEntry

  For Each entry In New EnumerationAdapter(New EnumerationMethod(AddressOf file.entries))

  If Not entry.isDirectory() Then

  If filter Is Nothing Or filter(entry) Then

  Dim s As java.io.InputStream = file.getInputStream(entry)

  Try

  Dim fname As String = System.IO.Path.GetFileName(entry.getName())

  Dim newpath As String = System.IO.Path.Combine(path, System.IO.Path.GetDirectoryName(entry.getName()))

  System.IO.Directory.CreateDirectory(newpath)

  Dim dest As New java.io.FileOutputStream(System.IO.Path.Combine(newpath, fname))

  Try

  CopyStream(s, dest)

  Finally

  dest.close()

  End Try

  Finally

  s.close()

  End Try

  End If

  End If

  Next entry

  End Sub

  Public Shared Function CreateEmptyZipFile(ByRef fileName As String) As ZipFile

  Dim zosSPDownload As ZipOutputStream = New ZipOutputStream(New java.io.FileOutputStream(fileName))

  zosSPDownload.close()

  Return New ZipFile(fileName)

  End Function

  Public Shared Function UpdateZipFile(ByRef file As ZipFile, ByRef filter As FilterEntryMethod, ByRef newFiles() As String) As ZipFile

  Dim prev As String = file.getName()

  Dim tmp As String = System.IO.Path.GetTempFileName()

  Dim [to] As New ZipOutputStream(New java.io.FileOutputStream(tmp))

  Try

  CopyEntries(file, [to], filter)

  ' add entries here

  If Not (newFiles Is Nothing) Then

  Dim f As String

  For Each f In newFiles

  Dim z As New ZipEntry(f.Remove(0, System.IO.Path.GetPathRoot(f).Length))

  z.setMethod(ZipEntry.DEFLATED)

  [to].putNextEntry(z)

  Try

  Dim s As New java.io.FileInputStream(f)

  Try

  CopyStream(s, [to])

  Finally

  s.close()

  End Try

  Finally

  [to].closeEntry()

  End Try

  Next f

  End If

  Finally

  [to].close()

  End Try

  file.close()

  ' now replace the old file with the new one

  System.IO.File.Copy(tmp, prev, True)

  System.IO.File.Delete(tmp)

  Return New ZipFile(prev)

  End Function

  Public Overloads Shared Sub CopyEntries(ByRef from As ZipFile, ByRef [to] As ZipOutputStream)

  CopyEntries(from, [to], Nothing)

  End Sub

  Public Overloads Shared Sub CopyEntries(ByRef from As ZipFile, ByRef [to] As ZipOutputStream, ByRef filter As FilterEntryMethod)

  Dim entry As ZipEntry

  Try

  For Each entry In New EnumerationAdapter(New EnumerationMethod(AddressOf from.entries))

  If filter Is Nothing Or filter(entry) Then

  Dim s As java.io.InputStream = from.getInputStream(entry)

  Try

  [to].putNextEntry(entry)

  Try

  CopyStream(s, [to])

  Finally

  [to].closeEntry()

  End Try

  Finally

  s.close()

  End Try

  End If

  Next entry

  Catch ex As Exception

  MessageBox.Show(ex.Message.ToString)

  End Try

  End Sub

  End Class

   

  End Namespace

  If you want to see a working example visit www.ftpex.com

  
  
• Dynamic file manipulation