我的想法是从数据库读取到临时文件,然后从文件存取到ole空间。
但是我写的程序出错了,怎么也不对劲。
以下是一个将一个文件写入到数据库中,但是我再读出来的时候,文件的长度翻倍了。在数据库中该字段的属性是ole对象。不知道哪里出错了,请各位大虾帮帮忙
Sub FileStreamToField(fileName As String, ByRef fdObject As Field)
Dim sChunkHolder() As Byte
Dim lChunkCount As Long
Dim lChunkRemainder As Long
Dim filesize As Long
Dim I As Long
Dim fileNum As Integer
ReDim sChunkHolder(CHUNK_SIZE)
filesize = fdObject.fieldSize
result.Caption = filesize
fileNum = FreeFile
Open fileName For Binary As fileNum
'sChunkHolder = Space$(CHUNK_SIZE)
' 临 时 存 贮 块
filesize = (LOF(fileNum) - Seek(fileNum) + 1)
result.Caption = filesize
lChunkCount = (LOF(fileNum) - Seek(fileNum) + 1) \ CHUNK_SIZE ' 取 块 数
lChunkRemainder = (LOF(fileNum) - Seek(fileNum) + 1) Mod CHUNK_SIZE' 取 整 块 后 余 下 的 数 据
For I = 1 To lChunkCount
Get fileNum, , sChunkHolder
' 从 文 件 中 取 出 一 块
fdObject.AppendChunk (sChunkHolder)
' 将 块 写 入 字 段 中
Next
If lChunkRemainder > 0 Then
'sChunkHolder = Space$(lChunkRemainder)
' 临 时 存 贮 块
Get fileNum, , sChunkHolder
' 取 出 该 块
result.Caption = fdObject.fieldSize
fdObject.AppendChunk (sChunkHolder)
result.Caption = fdObject.fieldSize
' 写 入 字 段 中
End If
' 返 回
End Sub
但是我写的程序出错了,怎么也不对劲。
以下是一个将一个文件写入到数据库中,但是我再读出来的时候,文件的长度翻倍了。在数据库中该字段的属性是ole对象。不知道哪里出错了,请各位大虾帮帮忙
Sub FileStreamToField(fileName As String, ByRef fdObject As Field)
Dim sChunkHolder() As Byte
Dim lChunkCount As Long
Dim lChunkRemainder As Long
Dim filesize As Long
Dim I As Long
Dim fileNum As Integer
ReDim sChunkHolder(CHUNK_SIZE)
filesize = fdObject.fieldSize
result.Caption = filesize
fileNum = FreeFile
Open fileName For Binary As fileNum
'sChunkHolder = Space$(CHUNK_SIZE)
' 临 时 存 贮 块
filesize = (LOF(fileNum) - Seek(fileNum) + 1)
result.Caption = filesize
lChunkCount = (LOF(fileNum) - Seek(fileNum) + 1) \ CHUNK_SIZE ' 取 块 数
lChunkRemainder = (LOF(fileNum) - Seek(fileNum) + 1) Mod CHUNK_SIZE' 取 整 块 后 余 下 的 数 据
For I = 1 To lChunkCount
Get fileNum, , sChunkHolder
' 从 文 件 中 取 出 一 块
fdObject.AppendChunk (sChunkHolder)
' 将 块 写 入 字 段 中
Next
If lChunkRemainder > 0 Then
'sChunkHolder = Space$(lChunkRemainder)
' 临 时 存 贮 块
Get fileNum, , sChunkHolder
' 取 出 该 块
result.Caption = fdObject.fieldSize
fdObject.AppendChunk (sChunkHolder)
result.Caption = fdObject.fieldSize
' 写 入 字 段 中
End If
' 返 回
End Sub
打开vb6,新建工程。添加两个按钮,一个image控件
注意:Access中的photo字段类型为OLE对象.
SqlServer中的photo字段类型为Image'** 引用 Microsoft ActiveX Data Objects 2.5 Library 及以上版本
‘2.5版本以下不支持Stream对象
Dim iConcstr As String
Dim iConc As ADODB.Connection
'保存文件到数据库中
Sub s_SaveFile()
Dim iStm As ADODB.Stream
Dim iRe As ADODB.Recordset
Dim iConcstr As String '读取文件到内容
Set iStm = New ADODB.Stream
With iStm
.Type = adTypeBinary '二进制模式
.Open
.LoadFromFile App.Path + "\test.jpg"
End With
'打开保存文件的表
Set iRe = New ADODB.Recordset
With iRe
.Open "select * from img", iConc, 1, 3
.AddNew '新增一条记录
.Fields("photo") = iStm.Read
.Update
End With
'完成后关闭对象
iRe.Close
iStm.Close
End Sub
Sub s_ReadFile()
Dim iStm As ADODB.Stream
Dim iRe As ADODB.Recordset
'打开表
Set iRe = New ADODB.Recordset
‘得到最新添加的纪录
iRe.Open "select top 1 * from img order by id desc", iConc, adOpenKeyset, adLockReadOnly
'保存到文件
Set iStm = New ADODB.Stream
With iStm
.Mode = adModeReadWrite
.Type = adTypeBinary
.Open
.Write iRe("photo")
‘这里注意了,如果当前目录下存在test1.jpg,会报一个文件写入失败的错误.
.SaveToFile App.Path & "\test1.jpg"
End With
Image1.Picture = LoadPicture(App.Path & "\test1.jpg")
'关闭对象
iRe.Close
iStm.Close
End Sub
Private Sub Command1_Click()
Call s_ReadFile
End Sub
Private Sub Command2_Click()
Call s_SaveFile
End Sub
Private Sub Form_Load()
'数据库连接字符串
iConcstr = "Provider=Microsoft.Jet.OLEDB.4.0;Persist Security Info=False" & _
";Data Source=F:\csdn_vb\database\保存图片\access图片\img.mdb"‘下面的语句是连接sqlserver数据库的.
‘iConcstr = "Provider=SQLOLEDB.1;Persist Security Info=True;" & _
‘ "User ID=sa;Password=;Initial Catalog=test;Data Source=yang"
Set iConc = New ADODB.Connection
iConc.Open iConcstr
End Sub
Private Sub Form_Unload(Cancel As Integer)
iConc.Close
Set iConc = Nothing
End Sub
[email protected],不胜感谢。