Private Sub SaveFile() '保存文件到数据库中
On Error Resume Next
Dim Stm As New ADODB.Stream '使用ADODB.Stream来保存/读取文件到数据库
'读取文件到内存(二进制模式)
With Stm
.Type = adTypeBinary
.Open
.LoadFromFile DtFlag
End With
RssW.Fields("dtwz") = Stm.Read
RssW.Update
Stm.Close
Set Stm = Nothing
End Sub
Private Sub ReadFile()
On Error Resume Next
Dim Stm As New ADODB.Stream
'保存到文件
With Stm
.Mode = adModeReadWrite
.Type = adTypeBinary
.Open
.Write RssW("dtwz")
.SaveToFile App.Path + "\image.jpg"
End With
DtFlag = App.Path + "\image.jpg"
Stm.Close
Set Stm = Nothing
End Sub
看看这个能不能看明白了
'-----------------------------------------------------------
'将图像文件转换成长二进制数据并写入到数据库中
'--Stanley 2007/05/18
'-----------------------------------------------------------
Public Sub SaveFileToDB(Fld As ADODB.Field, DiskFile As String)
Dim byteData() As Byte '定义数据块数组
Dim NumBlocks As Long '定义数据块个数
Dim FileLength As Long '标识文件长度
Dim LeftOver As Long '定义剩余字节长度
Dim SourceFile As Long '定义自由文件号
Dim i As Long '定义循环变量
Const BLOCKSIZE = 4096 '每次读写块的大小
On Error GoTo ErrorHandle
SourceFile = FreeFile '提供一个尚未使用的文件号
Open DiskFile For Binary Access Read As SourceFile '打开文件
FileLength = LOF(SourceFile) '得到文件长度
If FileLength = 0 Then '判断文件是否存在
Close SourceFile
MsgBox DiskFile & "无内容或不存在!", vbOKOnly + vbCritical, "提示"
Exit Sub
Else
NumBlocks = FileLength \ BLOCKSIZE '得到数据块的个数
LeftOver = FileLength Mod BLOCKSIZE '得到剩余字节数
Fld.value = Null
ReDim byteData(BLOCKSIZE) '重新定义数据块的大小
For i = 1 To NumBlocks
Get SourceFile, , byteData() ' 读到内存块中
Fld.AppendChunk byteData() '写入FLD
Next i
ReDim byteData(LeftOver) '重新定义数据块的大小
Get SourceFile, , byteData() '读到内存块中
Fld.AppendChunk byteData() '写入FLD
Close SourceFile '关闭源文件
End If
Exit Sub
ErrorHandle:
MsgBox Err.Description, vbOKOnly + vbCritical, "读图像文件出错!"
End Sub
'-----------------------------------------------------------
'从数据库中读取长二进制数据并写入到图像文件中
'--Stanley 2007/05/18
'-----------------------------------------------------------
Public Function ReadDBToFile(Fld As ADODB.Field, DiskFile As String) As Boolean
Dim FileNumber As Integer '文件号
Dim DataLen As Long '文件长度
Dim Chunks As Long '数据块数
Dim ChunkAry() As Byte '数据块数组
Dim ChunkSize As Long '数据块大小
Dim Fragment As Long '零碎数据大小
Dim lngI As Long '计数器
On Error GoTo ErrorHandle
ReadDBToFile = False
ChunkSize = 2048 '定义块大小为 2K
DataLen = Fld.ActualSize '获得图像大小
If DataLen < 8 Then Exit Function '图像大小小于8字节时认为不是图像信息
FileNumber = FreeFile '产生随机的文件号
Open DiskFile For Binary Access Write As FileNumber '打开存放图像数据文件
Chunks = DataLen \ ChunkSize '数据块数
Fragment = DataLen Mod ChunkSize '零碎数据
ReDim ChunkAry(ChunkSize - 1) '为数据块重新开辟空间
For lngI = 1 To Chunks '循环读出所有块
ChunkAry = Fld.GetChunk(ChunkSize) '在数据库中连续读数据块
Put FileNumber, , ChunkAry() '将数据块写入文件中
Next lngI
If Fragment > 0 Then '有零碎数据,则先读该数据
ReDim ChunkAry(Fragment - 1)
ChunkAry = Fld.GetChunk(Fragment)
Put FileNumber, , ChunkAry '写入文件
End If
Close FileNumber '关闭文件
ReadDBToFile = True
Exit Function
ErrorHandle:
ReadDBToFile = False
MsgBox Err.Description, vbOKOnly + vbCritical, "读图像数据出错!"
End Function