用VB6读写数据库中的图片 1，以人名和相关图片为例说明，数据库为Access，有如下字段：Name char,picture OLE object,FileLength
Number。当为ms sql时，将picture改为lob即可。
2，示例包含control：commom dialog,picture,listbox。
源码如下：
Option Explicit Private Declare Function GetTempFileName Lib "kernel32" Alias "GetTempFileNameA" (ByVal lpszPath As
String, ByVal lpPrefixString As String, ByVal wUnique As Long, ByVal lpTempFileName As String) As Long
Private Declare Function GetTempPath Lib "kernel32" Alias "GetTempPathA" (ByVal nBufferLength As Long,
ByVal lpBuffer As String) As Long
Private Const MAX_PATH = 260 Private m_DBConn As ADODB.Connection Private Const BLOCK_SIZE = 10000
注释： Return a temporary file name.
Private Function TemporaryFileName() As String
Dim temp_path As String
Dim temp_file As String
Dim length As Long 注释： Get the temporary file path.
temp_path = Space$(MAX_PATH)
length = GetTempPath(MAX_PATH, temp_path)
temp_path = Left$(temp_path, length) 注释： Get the file name.
temp_file = Space$(MAX_PATH)
GetTempFileName temp_path, "per", 0, temp_file
TemporaryFileName = Left$(temp_file, InStr(temp_file, Chr$(0)) - 1)
End Function
Private Sub Form_Load()
Dim db_file As String
Dim rs As ADODB.Recordset 注释： Get the database file name.
db_file = App.Path
If Right$(db_file, 1) <> "" Then db_file = db_file & ""
db_file = db_file & "dbpict.mdb" 注释： Open the database connection.
Set m_DBConn = New ADODB.Connection
m_DBConn.Open _
"Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=" & db_file & ";" & _
"Persist Security Info=False" 注释： Get the list of people.
Set rs = m_DBConn.Execute("SELECT Name FROM People ORDER BY Name", , adCmdText)
Do While Not rs.EOF
lstPeople.AddItem rs!Name
rs.MoveNext
Loop rs.Close
Set rs = Nothing
End Sub
Private Sub Form_Resize()
lstPeople.Height = ScaleHeight
End Sub
注释： Display the clicked person.
Private Sub lstPeople_Click()
Dim rs As ADODB.Recordset
Dim bytes() As Byte
Dim file_name As String
Dim file_num As Integer
Dim file_length As Long
Dim num_blocks As Long
Dim left_over As Long
Dim block_num As Long
Dim hgt As Single picPerson.Visible = False
Screen.MousePointer = vbHourglass
DoEvents 注释： Get the record.
Set rs = m_DBConn.Execute("SELECT * FROM People WHERE Name=注释：" & _
lstPeople.Text & "注释：", , adCmdText)
If rs.EOF Then Exit Sub 注释： Get a temporary file name.
file_name = TemporaryFileName() 注释： Open the file.
file_num = FreeFile
Open file_name For Binary As #file_num 注释： Copy the data into the file.
file_length = rs!FileLength
num_blocks = file_length / BLOCK_SIZE
left_over = file_length Mod BLOCK_SIZE For block_num = 1 To num_blocks
bytes() = rs!Picture.GetChunk(BLOCK_SIZE)
Put #file_num, , bytes()
Next block_num If left_over > 0 Then
bytes() = rs!Picture.GetChunk(left_over)
Put #file_num, , bytes()
End If Close #file_num 注释： Display the picture file.
picPerson.Picture = LoadPicture(file_name)
picPerson.Visible = True Width = picPerson.Left + picPerson.Width + Width - ScaleWidth
hgt = picPerson.Top + picPerson.Height + Height - ScaleHeight
If hgt < 1440 Then hgt = 1440
Height = hgt Kill file_name
Screen.MousePointer = vbDefault
End Sub Private Sub mnuRecordAdd_Click()
Dim rs As ADODB.Recordset
Dim person_name As String
Dim file_num As String
Dim file_length As String
Dim bytes() As Byte
Dim num_blocks As Long
Dim left_over As Long
Dim block_num As Long person_name = InputBox("Name")
If Len(person_name) = 0 Then Exit Sub dlgPicture.Flags = _
cdlOFNFileMustExist Or _
cdlOFNHideReadOnly Or _
cdlOFNExplorer
dlgPicture.CancelError = True
dlgPicture.Filter = "Graphics Files|*.bmp;*.ico;*.jpg;*.gif" On Error Resume Next
dlgPicture.ShowOpen
If Err.Number = cdlCancel Then
Exit Sub
ElseIf Err.Number <> 0 Then
MsgBox "Error " & Format$(Err.Number) & _
" selecting file." & vbCrLf & Err.Description
Exit Sub
End If 注释： Open the picture file.
file_num = FreeFile
Open dlgPicture.FileName For Binary Access Read As #file_num file_length = LOF(file_num)
If file_length > 0 Then
num_blocks = file_length / BLOCK_SIZE
left_over = file_length Mod BLOCK_SIZE Set rs = New ADODB.Recordset
rs.CursorType = adOpenKeyset
rs.LockType = adLockOptimistic
rs.Open "Select Name, Picture, FileLength FROM People", m_DBConn rs.AddNew
rs!Name = person_name
rs!FileLength = file_length ReDim bytes(BLOCK_SIZE)
For block_num = 1 To num_blocks
Get #file_num, , bytes()
rs!Picture.AppendChunk bytes()
Next block_num If left_over > 0 Then
ReDim bytes(left_over)
Get #file_num, , bytes()
rs!Picture.AppendChunk bytes()
End If rs.Update
Close #file_num lstPeople.AddItem person_name
lstPeople.Text = person_name
End If
End Sub
Number。当为ms sql时，将picture改为lob即可。
2，示例包含control：commom dialog,picture,listbox。
源码如下：
Option Explicit Private Declare Function GetTempFileName Lib "kernel32" Alias "GetTempFileNameA" (ByVal lpszPath As
String, ByVal lpPrefixString As String, ByVal wUnique As Long, ByVal lpTempFileName As String) As Long
Private Declare Function GetTempPath Lib "kernel32" Alias "GetTempPathA" (ByVal nBufferLength As Long,
ByVal lpBuffer As String) As Long
Private Const MAX_PATH = 260 Private m_DBConn As ADODB.Connection Private Const BLOCK_SIZE = 10000
注释： Return a temporary file name.
Private Function TemporaryFileName() As String
Dim temp_path As String
Dim temp_file As String
Dim length As Long 注释： Get the temporary file path.
temp_path = Space$(MAX_PATH)
length = GetTempPath(MAX_PATH, temp_path)
temp_path = Left$(temp_path, length) 注释： Get the file name.
temp_file = Space$(MAX_PATH)
GetTempFileName temp_path, "per", 0, temp_file
TemporaryFileName = Left$(temp_file, InStr(temp_file, Chr$(0)) - 1)
End Function
Private Sub Form_Load()
Dim db_file As String
Dim rs As ADODB.Recordset 注释： Get the database file name.
db_file = App.Path
If Right$(db_file, 1) <> "" Then db_file = db_file & ""
db_file = db_file & "dbpict.mdb" 注释： Open the database connection.
Set m_DBConn = New ADODB.Connection
m_DBConn.Open _
"Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=" & db_file & ";" & _
"Persist Security Info=False" 注释： Get the list of people.
Set rs = m_DBConn.Execute("SELECT Name FROM People ORDER BY Name", , adCmdText)
Do While Not rs.EOF
lstPeople.AddItem rs!Name
rs.MoveNext
Loop rs.Close
Set rs = Nothing
End Sub
Private Sub Form_Resize()
lstPeople.Height = ScaleHeight
End Sub
注释： Display the clicked person.
Private Sub lstPeople_Click()
Dim rs As ADODB.Recordset
Dim bytes() As Byte
Dim file_name As String
Dim file_num As Integer
Dim file_length As Long
Dim num_blocks As Long
Dim left_over As Long
Dim block_num As Long
Dim hgt As Single picPerson.Visible = False
Screen.MousePointer = vbHourglass
DoEvents 注释： Get the record.
Set rs = m_DBConn.Execute("SELECT * FROM People WHERE Name=注释：" & _
lstPeople.Text & "注释：", , adCmdText)
If rs.EOF Then Exit Sub 注释： Get a temporary file name.
file_name = TemporaryFileName() 注释： Open the file.
file_num = FreeFile
Open file_name For Binary As #file_num 注释： Copy the data into the file.
file_length = rs!FileLength
num_blocks = file_length / BLOCK_SIZE
left_over = file_length Mod BLOCK_SIZE For block_num = 1 To num_blocks
bytes() = rs!Picture.GetChunk(BLOCK_SIZE)
Put #file_num, , bytes()
Next block_num If left_over > 0 Then
bytes() = rs!Picture.GetChunk(left_over)
Put #file_num, , bytes()
End If Close #file_num 注释： Display the picture file.
picPerson.Picture = LoadPicture(file_name)
picPerson.Visible = True Width = picPerson.Left + picPerson.Width + Width - ScaleWidth
hgt = picPerson.Top + picPerson.Height + Height - ScaleHeight
If hgt < 1440 Then hgt = 1440
Height = hgt Kill file_name
Screen.MousePointer = vbDefault
End Sub Private Sub mnuRecordAdd_Click()
Dim rs As ADODB.Recordset
Dim person_name As String
Dim file_num As String
Dim file_length As String
Dim bytes() As Byte
Dim num_blocks As Long
Dim left_over As Long
Dim block_num As Long person_name = InputBox("Name")
If Len(person_name) = 0 Then Exit Sub dlgPicture.Flags = _
cdlOFNFileMustExist Or _
cdlOFNHideReadOnly Or _
cdlOFNExplorer
dlgPicture.CancelError = True
dlgPicture.Filter = "Graphics Files|*.bmp;*.ico;*.jpg;*.gif" On Error Resume Next
dlgPicture.ShowOpen
If Err.Number = cdlCancel Then
Exit Sub
ElseIf Err.Number <> 0 Then
MsgBox "Error " & Format$(Err.Number) & _
" selecting file." & vbCrLf & Err.Description
Exit Sub
End If 注释： Open the picture file.
file_num = FreeFile
Open dlgPicture.FileName For Binary Access Read As #file_num file_length = LOF(file_num)
If file_length > 0 Then
num_blocks = file_length / BLOCK_SIZE
left_over = file_length Mod BLOCK_SIZE Set rs = New ADODB.Recordset
rs.CursorType = adOpenKeyset
rs.LockType = adLockOptimistic
rs.Open "Select Name, Picture, FileLength FROM People", m_DBConn rs.AddNew
rs!Name = person_name
rs!FileLength = file_length ReDim bytes(BLOCK_SIZE)
For block_num = 1 To num_blocks
Get #file_num, , bytes()
rs!Picture.AppendChunk bytes()
Next block_num If left_over > 0 Then
ReDim bytes(left_over)
Get #file_num, , bytes()
rs!Picture.AppendChunk bytes()
End If rs.Update
Close #file_num lstPeople.AddItem person_name
lstPeople.Text = person_name
End If
End Sub
'存文件到数据库
Const BLOCKSIZE = 4096 '每次读写块的大小Public rsBinary As New ADODB.Recordset
Public Function AddFile(ByVal FileID As Long)
'Return boolean to decide whether refresh files list
Dim strBin As String * 3000
Dim btyGet() As Byte
Dim lngBlockIndex As Long
Dim lngBlocks As Long
Dim lngLastBlock As Long
Dim lngPosition As Long
Dim lngFileLenth As Long
Dim lngIndex As Long
With frmBinary.CommonDialog1
'.InitDir = App.Path
.Filter = "All image files¦*.bmp;*.ico;*.jpg;*.gif¦Bitmap files¦*.bmp¦Icon files¦*.ico¦All files¦*.*"
.filename = ""
On Error GoTo ErrorHandle
.ShowOpen
On Error GoTo 0
If .filename <> "" Then
Open .filename For Binary As #1
lngFileLenth = LOF(1)
lngPosition = 0
'Get block count for loop
lngBlocks = lngFileLenth / BLOCKSIZE
'Get lngth of last block for the last read
lngLastBlock = lngFileLenth Mod BLOCKSIZE
TypeCode = Right(.filename, 3)
rsBinary.AddNew
rsBinary.Fields("typecode") = TypeCode
For lngBlockIndex = 1 To lngBlocks
ReDim btyGet(BLOCKSIZE)
Get #1, , btyGet()
rsBinary.Fields("content").AppendChunk btyGet()
lngPosition = lngPosition + BLOCKSIZE
Next If lngLastBlock > 0 Then
ReDim btyGet(lngLastBlock)
Get #1, , btyGet()
rsBinary.Fields("content").AppendChunk btyGet()
End If
rsBinary.Fields("id") = FileID
rsBinary.Update
rsBinary.UpdateBatch
Close #1
AddFile = True
MsgBox "Save finished", vbInformation
Else
AddFile = False
End If
End With
Exit Function
ErrorHandle:
AddFile = False
End Function
'从数据库取文件出来
Public Sub SaveFile(ByVal FileID As Long)
Dim lngBlockCount As Long
Dim lngLastBlock As Long
Dim lngI As Long
Dim btyBlock() As Byte
Dim lngResult As Long
If rsBinary.EOF And rsBinary.BOF Then Exit Sub
rsBinary.Requery
rsBinary.MoveFirst
rsBinary.Find " id=" & FileID
If Not rsBinary.EOF Then
With frmBinary.CommonDialog1
.filename = "TempSave" & "." & rsBinary.Fields("typecode")
'.InitDir = App.Path
'If user cancel save the goto handle
On Error GoTo ErrorHandle
.ShowSave
If .filename <> "" Then
lngBlockCount = rsBinary.Fields("content").ActualSize \ BLOCKSIZE
lngLastBlock = rsBinary.Fields("content").ActualSize Mod BLOCKSIZE
If Dir(.filename) <> "" Then
If MsgBox("File " & .filename & " is exist,overwrite?", vbYesNo + vbQuestion) = vbYes Then
Kill .filename
Else
Exit Sub
End If
Else
End If
Open .filename For Binary As #1
ReDim btyBinary(BLOCKSIZE)
For lngI = 1 To lngBlockCount
btyBlock() = rsBinary.Fields("content").GetChunk(BLOCKSIZE)
Put #1, , btyBlock
Next
If lngLastBlock <> 0 Then
ReDim btyBlock(lngLastBlock)
btyBlock() = rsBinary.Fields("content").GetChunk(lngLastBlock)
Put #1, , btyBlock
End If
Close #1
MsgBox .filename & " is saved", vbInformation
Else
End If
End With
End If
Exit Sub
ErrorHandle:
End Sub
Public Sub P_Open()
With rsBinary
If .State = adStateOpen Then
.Close
End If
.ActiveConnection = adoCN
.CursorLocation = adUseClient
.CursorType = adOpenDynamic
.LockType = adLockBatchOptimistic
.Source = "SELECT * FROM sss" 'sss库字段id ,content,typecode
.Open
End WithEnd Sub
'* Save/Retrieve Image Data From SQL Server DataBase Using
'* ADOStream Objects.
'***************************************************************
'* Code By: Michael P. Gerety
'***************************************************************Dim rstRecordset As ADODB.Recordset
Dim cnnConnection As ADODB.Connection
Dim strStream As ADODB.Stream'以下在窗体中
'*Setup:
'*Create a form and place 3 command buttons named:
'*cmdLoad, cmdSelectSave, and cmdClear
'*Place a CommonDialog Control Named Dialog
'*Place an ImageBox (or PictureBox) named Image1
'** The field type in Sql Server must be "Image"
'** Everywhere you see "***" in the code is where you must enter
'** your own data.Private Sub cmdClear_Click()
Image1.Picture = Nothing
End SubPrivate Sub cmdLoad_Click()
If Not LoadPictureFromDB(rstRecordset) Then
MsgBox "Invalid Data Or No Picture In DB"
End If
End SubPrivate Sub cmdSelectSave_Click()
'Open Dialog Box
With dlgDialog
.DialogTitle = "Open Image File...."
.Filter = "Image Files (*.gif; *.bmp)| *.gif;*.bmp"
.CancelError = True
procReOpen:
.ShowOpen
If .FileName = "" Then
MsgBox "Invalid filename or file not found.", _
vbOKOnly + vbExclamation, "Oops!"
GoTo procReOpen
Else
If Not SavePictureToDB(rstRecordset, .FileName) Then
MsgBox "Save was unsuccessful :(", vbOKOnly + _
vbExclamation, "Oops!"
Exit Sub
End If
End If
End With
End SubPrivate Sub Form_Load()
Set cnnConnection = New ADODB.Connection
Set rstRecordset = New ADODB.Recordset cnnConnection.Open ("Provider=SQLOLEDB; " & _
"data Source=**YourServer**;" & _
"Initial Catalog=**YourDatabase**; " & _
"User Id=**YourUID**;Password=***YourPass***")
rstRecordset.Open "Select * from YourTable", cnnConnection, _
adOpenKeyset, adLockOptimistic
End Sub
Public Function LoadPictureFromDB(RS As ADODB.Recordset) On Error GoTo procNoPicture
'If Recordset is Empty, Then Exit
If RS Is Nothing Then
GoTo procNoPicture
End If
Set strStream = New ADODB.Stream
strStream.Type = adTypeBinary
strStream.Open
strStream.Write RS.Fields("**YourImageField**").Value
strStream.SaveToFile "C:\Temp.bmp", adSaveCreateOverWrite
Image1.Picture = LoadPicture("C:\Temp.bmp")
Kill ("C:\Temp.bmp")
LoadPictureFromDB = TrueprocExitFunction:
Exit Function
procNoPicture:
LoadPictureFromDB = False
GoTo procExitFunction
End FunctionPublic Function SavePictureToDB(RS As ADODB.Recordset, _
sFileName As String) On Error GoTo procNoPicture
Dim oPict As StdPicture
Set oPict = LoadPicture(sFileName)
'Exit Function if this is NOT a picture file
If oPict Is Nothing Then
MsgBox "Invalid Picture File!", vbOKOnly, "Oops!"
SavePictureToDB = False
GoTo procExitSub
End If
RS.AddNew
Set strStream = New ADODB.Stream
strStream.Type = adTypeBinary
strStream.Open
strStream.LoadFromFile sFileName
RS.Fields("***YourImageField***").Value = strStream.Read
Image1.Picture = LoadPicture(sFileName)
SavePictureToDB = True
procExitSub:
Exit Function
procNoPicture:
SavePictureToDB = False
GoTo procExitSub
End Function