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
1.将图片控件与Data控件帮定
2.通过代码来进行操作
第一种方法大家经常会在互联网上查到，本文主要介绍第二种方法。
应用的数据库是Access或SQL Server.一 建立数据库
Access数据库中的图片字段选择的类型为Ole 对象，可以向该字段写入二进制数据
SQL Server 数据库图片字段选择类型为image 或 varbinary。二 写入图片
从图片文件读取文件的内容，直接写入对应的图片字段，应用字段的AppendChunk方法。代码如下：
Pulic Function SaveImageToDatabase(ByVal FileName As String, fField As Field) As Boolean
Dim DataFile As Integer
Dim Chunks As Integer
Dim Fragment As Integer
Dim lLen As Long
Dim Chunk() As Byte
Dim i As Integer
Const ChunkSize As Integer = 4096
DataFile = FreeFile()
Open FileName For Binary Access Read As DataFile
lLen = LOF(DataFile)
If lLen = 0 Then
Close DataFile
SaveImageToDatabase = False
Exit Function
Else
Chunks = lLen \ ChunkSize
Fragment = lLen Mod ChunkSize
ReDim Chunk(Fragment)
Get DataFile, , Chunk
fField.AppendChunk Chunk
ReDim Chunk(ChunkSize)
For i = 1 To Chunks
Get DataFile, , Chunk
fField.AppendChunk Chunk
Next i
Close DataFile
End If
SaveImageToDatabase = True
End Function三 读取图片
从对应的图片字段中读取字段的内容，写入到一个图片文件中。应用了字段的GetChunk方法。代码如下： Public Function DisplayImageFromDatabase(ByRef FileName As String, fField As Field) As Boolean Dim DataFile As Integer
Dim Chunks As Integer
Dim Fragment As Integer
Dim lLen As Long
Dim Chunk() As Byte
Dim i As Integer
Dim fos As New Scripting.FileSystemObject
Dim tfolder As Folder
Dim tfile As String
Dim TemporaryFolder As String
if FileName="" then
Set tfolder = fos.GetSpecialFolder(2) '取得系统临时文件夹
TemporaryFolder = tfolder.Path
tfile = fos.GetTempName()
tfile = Left(tfile, Len(tfile) - 3)
tfile = tfile & "BMP"
FileName = TemporaryFolder & "\" & tfile
end if
Const ChunkSize As Integer = 4096
lLen = fField.ActualSize
If lLen = 0 Then
DisplayImageFromDatabase = False
FileName = ""
Exit Function
End If
DataFile = FreeFile()
Open FileName For Binary Access Write As DataFile
Chunks = lLen \ ChunkSize
Fragment = lLen Mod ChunkSize
ReDim Chunk(Fragment)
Chunk() = fField.GetChunk(Fragment)
Put DataFile, , Chunk()
For i = 1 To Chunks
Chunk() = fField.GetChunk(ChunkSize)
Put DataFile, , Chunk()
Next i
Close DataFile
DisplayImageFromDatabase = True
End Function四 调用上述两个函数的方法
数据表名称是Stamp,其中有两个字段 sta_ID,sta_Image. 字段sta_Image是图片字段。 1 写入图片
Private Sub SavePicture(ByVal ID As Long, ByVal sFile As String)
Dim sSQL As String
Dim recX As New ADODB.Recordset
sSQL = "Select sta_Image from stamp Where sta_ID=" & ID
recX.Open sSQL, cn, adOpenDynamic, adLockOptimistic
SaveImageToDatabase sFile, recX.Fields(0)
recX.UpdateBatch adAffectCurrent
recX.Close
End Sub
2 显示图片
Private Sub ShowImage(byval lID as long)
Dim b As Boolean
Dim ssql As String
Dim recX As New ADODB.Recordset
b=False
ssql = "Select sta_Image From stamp Where sta_ID=" & lID
recX.Open ssql, cn, adOpenDynamic
Dim sFile As String
b = DisplayImageFromDataBase(sFile, recX.Fields(0))
recX.Close If b = True Then
Set Picture1.Picture = LoadPicture(sFile)
Else
Picture1.Cls
End If
Picture1.Refresh
End Sub