（转载）VB 查询Oracle中blob类型字段,并且把blob中的图片以流的方式显示在Image上

原文摘自：http://heisetoufa.iteye.com/blog/504068

'模块代码
Private Declare Function CreateStreamOnHGlobal Lib "ole32" (ByVal hGlobal As Long, ByVal fDeleteOnRelease As Long, ppstm As Any) As Long
Private Declare Function OleLoadPicture Lib "olepro32" (pStream As Any, ByVal lSize As Long, ByVal fRunmode As Long, riid As Any, ppvObj As Any) As Long
Private Declare Function CLSIDFromString Lib "ole32" (ByVal lpsz As Any, pclsid As Any) As Long
Private Declare Function GlobalAlloc Lib "kernel32" (ByVal uFlags As Long, ByVal dwBytes As Long) As Long
Private Declare Function GlobalLock Lib "kernel32" (ByVal hMem As Long) As Long
Private Declare Function GlobalUnlock Lib "kernel32" (ByVal hMem As Long) As Long
Private Declare Sub MoveMemory Lib "kernel32" Alias "RtlMoveMemory" (pDest As Any, pSource As Any, ByVal dwLength As Long)
Private Declare Function GlobalFree Lib "kernel32" (ByVal hMem As Long) As Long

Public Type GUID ' 16 bytes (128 bits)
'dwData1 As Long ' 4 bytes
'wData2 As Integer ' 2 bytes
'wData3 As Integer ' 2 bytes
abData4(7) As Byte ' 8 bytes, zero based
End Type


Public Function PictureFromByteStream(B() As Byte) As IPicture
    Dim hMem        As Long
    Dim lpMem       As Long
    Dim LowerBound  As Long
    Dim ByteCount   As Long
    Dim IID_IPicture As GUID
    Dim istm        As stdole.IUnknown
    
    LowerBound = LBound(B)
    ByteCount = UBound(B) - LowerBound + 1
    
    hMem = GlobalAlloc(&H2, ByteCount)
    
    If hMem <> 0 Then
        
        lpMem = GlobalLock(hMem)
        
        If lpMem <> 0 Then
            
            MoveMemory ByVal lpMem, B(LowerBound), ByteCount
            
            GlobalUnlock hMem
            
            If CreateStreamOnHGlobal(hMem, 1, istm) = 0 Then
                
                If CLSIDFromString(StrPtr("{7BF80980-BF32-101A-8BBB-00AA00300CAB}"), IID_IPicture) = 0 Then
                    
                    OleLoadPicture ByVal ObjPtr(istm), ByteCount, 0, IID_IPicture, PictureFromByteStream
                    
                End If
                
            End If
            
        End If
        
    End If
    
End Function

Public Sub Combo1_Click()

Dim adoCnn As ADODB.Connection
    Dim rstOra As ADODB.Recordset
    Dim intI   As Integer
     
    Set adoCnn = New ADODB.Connection
    Set rstOra = New ADODB.Recordset
                                     
    adoCnn.ConnectionString = "Provider=OraOLEDB.Oracle;User ID=dzjc;password=zlkj;Data Source=dzjc_2005;" '读blob字段要用Provider=OraOLEDB.Oracle
         
    adoCnn.CursorLocation = adUseClient
    adoCnn.Open
           
    rstOra.CursorLocation = adUseClient
   
    rstOra.ActiveConnection = adoCnn
    rstOra.Open "SELECT zp FROM dzjc.dzjc_wfzp WHERE xh = '5'"
          
    'Set Image1.DataSource = rstOra
          
    Set Image1.Picture = PictureFromByteStream(rstOra.Fields("zp").Value)

End Sub