将多个文件写到一个文件(并合文件)，也可从该并合文件中获得其中某个文件的流（具体不多写了，压缩功能未加进，有兴趣留言）

Imports System.IO

Imports System.Runtime.InteropServices

Imports System.ComponentModel

Public Class Form1

Dim cfm As New CoalescentFileManager

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

For Each x In My.Computer.FileSystem.GetFiles(My.Computer.FileSystem.SpecialDirectories.MyPictures, FileIO.SearchOption.SearchTopLevelOnly, ("*.jpg"))

cfm.AddSourceFile(x)

Console.WriteLine(x)

Next

'

cfm.WriteCoalescentFile(Environment.GetFolderPath(Environment.SpecialFolder.Desktop) & "/" & "xx.dat")

cfm.LoadCoalescentFile(Environment.GetFolderPath(Environment.SpecialFolder.Desktop) & "/" & "xx.dat")

ListBox1.Items.AddRange(cfm.CurrentCoalescentFile.NameList)

'cfm.CurrentCoalescentFile.RevertCoalescentFileToDirectory(Environment.GetFolderPath(Environment.SpecialFolder.Desktop) & "/xx/")

End Sub

Private Sub ListBox1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged

Me.BackgroundImage = Image.FromStream(cfm.CurrentCoalescentFile.GetStream(ListBox1.SelectedIndex))

End Sub

End Class

Public Class CoalescentFileManager

Dim _fullFilenameList As New List(Of String)

Dim _coaFileLoaded As Boolean

Dim _cf As CoalescentFile

Sub New()

End Sub

Sub AddSourceFile(ByVal source As String)

If Not File.Exists(source) Then Return

_fullFilenameList.Add(source)

End Sub

Public Sub WriteCoalescentFile(ByVal filename As String)

WriteCoalescentFile(filename, False)

End Sub

Public Sub WriteCoalescentFile(ByVal filename As String, ByVal useDeflate As Boolean)

Using fs As New FileStream(filename, FileMode.Create, FileAccess.ReadWrite)

Dim bw As New BinaryWriter(fs)

'

bw.Write("CoalescentFile")

'

bw.Write(useDeflate)

'占用了4字节

bw.Write(_fullFilenameList.Count)

For Each f In _fullFilenameList

Dim fi As New FileInfo(f)

'每个占用8字节

bw.Write(fi.Length)

fi = Nothing

Next

For Each f In _fullFilenameList

bw.Write(Path.GetFileName(f))

Next

For Each f In _fullFilenameList

bw.Write(File.ReadAllBytes(f))

bw.Flush()

Next

bw.Close()

End Using

End Sub

Public Sub LoadCoalescentFile(ByVal coalescentFile As String)

If Not File.Exists(coalescentFile) Then

Throw New InvalidCoalescentFileException("所指示文件不存在。")

End If

Using fs As New FileStream(coalescentFile, FileMode.Open, FileAccess.Read)

Dim br As New BinaryReader(fs)

Dim headStr As String = br.ReadString

If headStr <> "CoalescentFile" Then

Throw New InvalidCoalescentFileException("该文件不是有效的合并文件。")

End If

End Using

_cf = New CoalescentFile(coalescentFile)

_coaFileLoaded = True

End Sub

Public ReadOnly Property CurrentCoalescentFile() As CoalescentFile

Get

Return _cf

End Get

End Property

Public Class CoalescentFile

Dim _shortNameList As List(Of String)

Dim _fileLengthList As List(Of Long)

Dim _fileCount As Integer

Dim _isZip As Boolean

Dim _cf As String

Dim _contentStartPos As Long

Sub New(ByVal cf As String)

_shortNameList = New List(Of String)

_fileLengthList = New List(Of Long)

_cf = cf

Using fs As New FileStream(_cf, FileMode.Open, FileAccess.Read)

Dim br As New BinaryReader(fs)

br.ReadString()

_isZip = br.ReadBoolean

_fileCount = br.ReadInt32

For i = 1 To _fileCount

_fileLengthList.Add(br.ReadInt64())

Next

For i = 1 To _fileCount

_shortNameList.Add(br.ReadString)

Next

_contentStartPos = fs.Position

br.Close()

End Using

End Sub

Public Sub RevertCoalescentFileToDirectory(ByVal dir As String)

If Not Directory.Exists(dir) Then Directory.CreateDirectory(dir)

Using fs As New FileStream(_cf, FileMode.Open, FileAccess.Read)

Dim br As New BinaryReader(fs)

fs.Position = _contentStartPos

For i = 0 To _fileCount - 1

Dim buffer = br.ReadBytes(_fileLengthList(i))

File.WriteAllBytes(dir & _shortNameList(i), buffer)

Next

br.Close()

End Using

End Sub

Public Sub WriteOneToFile(ByVal index As Integer, ByVal file As String)

Using fs As New FileStream(file, FileMode.Create, FileAccess.Write)

Using mems As MemoryStream = GetStream(index)

Dim bw As New BinaryWriter(fs)

'若用 memoryStream.GetBuffer 方法则会在末尾多出一些 空符(字符码为零)

bw.Write(mems.ToArray)

bw.Close()

End Using

End Using

End Sub

Public Function GetStream(ByVal index As Integer) As MemoryStream

Dim startPos As Long = _contentStartPos

For i = 0 To index - 1

startPos += _fileLengthList(i)

Next

Dim buffer As Byte()

Using fs As New FileStream(_cf, FileMode.Open, FileAccess.Read)

Dim br As New BinaryReader(fs)

fs.Position = startPos

buffer = br.ReadBytes(_fileLengthList(index))

br.Close()

End Using

Dim mems As MemoryStream

mems = New MemoryStream(buffer)

Erase buffer

GC.Collect()

Return mems

End Function

Public ReadOnly Property NameList() As String()

Get

Return _shortNameList.ToArray

End Get

End Property

Public ReadOnly Property FileCount() As Integer

Get

Return _fileCount

End Get

End Property

Public ReadOnly Property CurrentFile() As String

Get

Return _cf

End Get

End Property

Public ReadOnly Property IsDeflate() As Boolean

Get

Return _isZip

End Get

End Property

End Class

End Class

Public Class InvalidCoalescentFileException

Inherits Exception

Sub New(ByVal text As String)

MyBase.New(text)

End Sub

End Class