一段精简的使用 ADODB.Stream 读写"大字段"的 VB 代码!

'一段精简的读写"大字段"的代码,使用 ADODB.Stream

'Objects: Form1、Picture1

'引用 Microsoft ActiveX Data Objects 2.5 Libary

'或 Microsoft ActiveX Data Objects 2.6 Libary

Dim TempFileName As String

TempFileName = App.Path & "/TempFile.tmp"

Dim adoConnection As New ADODB.Connection

Dim adoRecordset As New ADODB.Recordset

adoConnection.Open "Provider=Microsoft.Jet.OLEDB.3.51;Persist Security Info=False;Data Source=" & App.Path & "/mmxdb97.mdb"

adoRecordset.Open "SELECT * FROM bmp", adoConnection, adOpenKeyset, adLockOptimistic ', adCmdTable

Debug.Print adoRecordset.Fields(1).Type '大字段

adoRecordset.AddNew

Dim adoStream As New ADODB.Stream

adoStream.Type = adTypeBinary

adoStream.Open

adoStream.LoadFromFile CommonDialog1.FileName

'将二进制文件写入大字段:

adoRecordset.Fields.Item(1).AppendChunk adoStream.Read

'================================

'从大字段读取二进制数据:

adoStream.Write adoRecordset.Fields.Item(1).GetChunk(adoRecordset.Fields.Item(1).ActualSize)

adoStream.SaveToFile TempFileName, IIf(Len(Trim(Dir(TempFileName, vbNormal + vbHidden))) > 0, adSaveCreateOverWrite, adSaveCreateNotExist)

Picture1.AutoSize = True

Picture1.Picture = LoadPicture(TempFileName)