Attribute VB_Name = "ImageFunc"
Const ChunkSize As Long = 100
Const BlockSize As Long = 100
Const TempFile As String = "tempfile.tmp"

Dim ByteData() As Byte '定義數據塊數組
Dim DiskFile As String '圖像文件名
Dim NumBlocks As Long  '定義數據塊個數
Dim FileLength As Long '標識文件長度
Dim LeftOver As Long   '定義剩余字節長度
Dim SourceFile As Long '定義自由文件號
Dim byteChunk() As Byte
Dim i As Long '定義循環變量

Public Sub ShowImage(Image1 As Image, Adodc1 As Adodc)
  Erase byteChunk()
  FieldSize = Adodc1.Recordset.Fields(8).ActualSize
  If FieldSize <= 0 Then
    Image1.Picture = LoadPicture("")
    Exit Sub
  End If
  '提供一個尚未使用的文件號
  SourceFile = FreeFile
  '打開文件
  Open TempFile For Binary Access Write As SourceFile
  '計算數據塊
  NumBlocks = FieldSize \ BlockSize
  LeftOver = FieldSize Mod BlockSize '得到剩余字節數
  '分塊讀取圖像數據，并寫入到文件中
  If LeftOver <> 0 Then
    ReDim byteChunk(LeftOver)
    byteChunk() = Adodc1.Recordset.Fields(8).GetChunk(LeftOver)
    Put SourceFile, , byteChunk()
  End If
  For i = 1 To NumBlocks
    ReDim byteChunk(BlockSize)
    byteChunk() = Adodc1.Recordset.Fields(8).GetChunk(BlockSize)
    Put SourceFile, , byteChunk()
  Next i
  Close SourceFile
  '將文件裝入到Image1控件中
  Image1.Picture = LoadPicture(TempFile)
  '刪除臨時文件
  Kill (TempFile)
End Sub


Public Sub SaveImage(ByVal ImageFile As String, Adodc1 As Adodc)

  Dim TmpBookNo As String

   If Adodc1.Recordset.BOF = True Or Adodc1.Recordset.EOF = True Then
    Exit Sub
  End If
  If ImageFile = "" Then
    Exit Sub
  End If
  TmpBookNo = Adodc1.Recordset.Fields(0)

  '提供一個尚未使用的文件號
  SourceFile = FreeFile
  '打開文件
  Open ImageFile For Binary Access Read As SourceFile
  '得到文件長度
  FileLength = LOF(SourceFile)
  '判斷文件是否存在
  If FileLength = 0 Then
    Close SourceFile
    MsgBox DiskFile & "無內容或不存在!"
  Else
    NumBlocks = FileLength \ BlockSize '得到數據塊的個數
    LeftOver = FileLength Mod BlockSize '得到剩余字節數
    Adodc1.Recordset.Fields(8).Value = Null
    ReDim ByteData(BlockSize) '重新定義數據塊的大小
    For i = 1 To NumBlocks
      Get SourceFile, , ByteData() '讀到內存塊中
      Adodc1.Recordset.Fields(8).AppendChunk ByteData()  '寫入FLD
    Next i
    ReDim ByteData(LeftOver) '重新定義數據塊的大小
    Get SourceFile, , ByteData() '讀到內存塊中
    Adodc1.Recordset.Fields(8).AppendChunk ByteData()  '寫入FLD
    Close SourceFile '關閉源文件
    Adodc1.Recordset.Update
  End If
End Sub