（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/

'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() 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 + 

    hMem = GlobalAlloc(&H2, ByteCount)

    If hMem <>  Then

        lpMem = GlobalLock(hMem)

        If lpMem <>  Then

            MoveMemory ByVal lpMem, B(LowerBound), ByteCount

            GlobalUnlock hMem

            If CreateStreamOnHGlobal(hMem, , istm) =  Then

                If CLSIDFromString(StrPtr("{7BF80980-BF32-101A-8BBB-00AA00300CAB}"), IID_IPicture) =  Then

                    OleLoadPicture ByVal ObjPtr(istm), ByteCount, , 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