重提：数据库图片读取（vb.net+Access）

古今多少事 2009-05-30 11:55:22

我的Access数据库中有一表MyName,表中有两字段：图片名称（文本类型）、图片（OLE对象类型）。代码如下：

Imports System.IO

Imports System.Data.OleDb



Public Class Form1

    Dim MyConnection As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Application.StartupPath & "\db1.mdb")

    Dim MyCommand As OleDbCommand

    Dim MyAdapter As OleDbDataAdapter

    Dim MyDataSet As New DataSet





    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        

        MyConnection.Open()

        MyCommand = New OleDbCommand("Select * from MyName", MyConnection)

        MyAdapter = New OleDbDataAdapter(MyCommand)

        MyAdapter.Fill(MyDataSet, "picture")

        'Me.DataGridView1.DataSource = MyDataSet

        'Me.DataGridView1.DataMember = "picture"



        Dim arrPicture() As Byte = CType(MyDataSet.Tables("picture").Rows(0)("图片"), Byte()) '将数据库中的图片转换成无符合字节数组

        Dim TempMemoryStream As New MemoryStream(arrPicture)

        PictureBox1.Image = Image.FromStream(TempMemoryStream)'错误就在此句

    End Sub

现在的问题是：执行到最后一句时提示“参数无效”，晕！请各位帮忙看下，就这一问题，由于一些原因，我暂时不想换其他的数据库。谢谢！

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yangxhdl 2010-02-25

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最后问题出在什么地方，我怎么没有看明白。我也是打开一个之前的数据库，出现同样的问题。请指教

哥是龙王 2009-06-07

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这说明你保存到库中的图片出现了问题，你的程序应该没问题，先把记录里面的图片保存成普通文件，看看有没有问题。

古今多少事 2009-06-07

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[Quote=引用 16 楼 fujiandragon 的回复:]
试试看这样行不行
PictureBox1.Image =Image.FromFile(Application.StartupPath & "\monkey.bmp")
[/Quote]

谢谢！这样会显示“内存不足”的错误。记得以前也试过。

哥是龙王 2009-06-07

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试试看这样行不行
PictureBox1.Image =Image.FromFile(Application.StartupPath & "\monkey.bmp")

古今多少事 2009-06-07

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[Quote=引用 14 楼 ASDFY 的回复:]
引用 12 楼 zgke 的回复:
我的意思不是保存到本地你是怎么保存到数据库的.

哦，是这样的，以前在VB6.0时做过相同的图片存取程序，现在就是借用以前的那个数据库，在.net中没有做过保存的操作。不会就是这个原因吧？请指教！
[/Quote]

呵呵，就是这个原因。问题解决了，太爽了……

有点奇怪，想不通啊，不过这个是次要的啦。马上结贴！谢谢大家！

sytsyt0329 2009-06-03

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应该不会是以前的vb6做数据库的原因

boyibyy 2009-06-02

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玩过来，玩过去！！！

zgke 2009-06-02

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我的意思不是保存到本地你是怎么保存到数据库的.

古今多少事 2009-06-02

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[Quote=引用 12 楼 zgke 的回复:]
我的意思不是保存到本地你是怎么保存到数据库的.
[/Quote]

哦，是这样的，以前在VB6.0时做过相同的图片存取程序，现在就是借用以前的那个数据库，在.net中没有做过保存的操作。不会就是这个原因吧？请指教！

古今多少事 2009-06-01

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不好意思，重贴一下：

Imports System.IO

Imports System.Data.OleDb



Public Class Form1

    Dim MyConnection As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Application.StartupPath & "\db2003.mdb")

    Dim MyCommand As OleDbCommand

    Dim MyAdapter As OleDbDataAdapter

    Dim MyDataSet As New DataSet





    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        

        MyConnection.Open()

        MyCommand = New OleDbCommand("Select * from 表1", MyConnection)

        MyAdapter = New OleDbDataAdapter(MyCommand)

        MyAdapter.Fill(MyDataSet, "picture")



        '＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊



        '从数据库读取图片暂时存储为monkey.bmp,然后加载到image控件里面

        Dim data As Byte() = MyDataSet.Tables("picture").Rows(0)("图片") '将数据库中的图片转换成无符号字节数组

        Dim myfilestream As New System.IO.FileStream(Application.StartupPath & "\monkey.bmp", IO.FileMode.Create)

        myfilestream.Write(data, 0, data.Length)

        myfilestream.Close()

        PictureBox1.Image = New Bitmap(Application.StartupPath & "\monkey.bmp") '错误和下面一样也在此句



        '＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊



        'Dim arrPicture() As Byte = CType(MyDataSet.Tables("picture").Rows(0)("图片"), Byte()) '将数据库中的图片转换成无符合字节数组

        'Dim TempMemoryStream As New MemoryStream(arrPicture)

        'PictureBox1.Image = Image.FromStream(TempMemoryStream) '错误就在此句

        

    End Sub

是这样保存的吗（星号部分）？错误提示一样，请帮着再看看，谢谢！

古今多少事 2009-06-01

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Imports System.IO

Imports System.Data.OleDb



Public Class Form1

    Dim MyConnection As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Application.StartupPath & "\db2003.mdb")

    Dim MyCommand As OleDbCommand

    Dim MyAdapter As OleDbDataAdapter

    Dim MyDataSet As New DataSet





    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        

        MyConnection.Open()

        MyCommand = New OleDbCommand("Select * from 表1", MyConnection)

        MyAdapter = New OleDbDataAdapter(MyCommand)

        MyAdapter.Fill(MyDataSet, "picture")



        '＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊



        '从数据库读取图片暂时存储为monkey.bmp,然后加载到image控件里面

        Dim data As Byte() = MyDataSet.Tables("picture").Rows(0)("图片") '将数据库中的图片转换成无符号字节数组

        Dim myfilestream As New System.IO.FileStream(Application.StartupPath & "\monkey.bmp", IO.FileMode.Create)

        myfilestream.Write(data, 0, data.Length)

        myfilestream.Close()

        PictureBox1.Image = New Bitmap(Application.StartupPath & "\monkey.bmp") '错误和下面一样也在此句



        '＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊



        'Dim arrPicture() As Byte = CType(MyDataSet.Tables("picture").Rows(0)("图片"), Byte()) '将数据库中的图片转换成无符合字节数组

        'Dim TempMemoryStream As New MemoryStream(arrPicture)

        'PictureBox1.Image = Image.FromStream(TempMemoryStream) '错误就在此句

        'Dim TempMemoryStream As New MemoryStream(arrPicture)

        'PictureBox1.Image = Image.FromStream(TempMemoryStream)

    End Sub

是这样保存的吗（星号部分）？错误提示一样，请帮着再看看，谢谢！

zgke 2009-06-01

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[Quote=引用 8 楼 ASDFY 的回复:]
引用 6 楼 zgke 的回复:
你给 Dim TempMemoryStream As New MemoryStream(arrPicture)
加个短先...检查下 arrPicture数据. ..但看前面的byte[] 和最后几个是否和保存的时候一样.一般都是保存的时候就损坏了数据.

谢谢你的回复！
刚才看了一下，前后是有差别的，保存前从byte[255]开始就是一连串的“？”，保存后还不到255就是“？”。不知这个问题如何解决？真是晕啊>>>>>
但在网上搜到的都是这样做的，你们都成功…
[/Quote]

贴出你的保存代码把.

zenowolf 2009-05-31

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TempMemoryStream 里数据是否存在
调试看看
支持～

古今多少事 2009-05-31

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[Quote=引用 6 楼 zgke 的回复:]
你给 Dim TempMemoryStream As New MemoryStream(arrPicture)
加个短先...检查下 arrPicture数据. ..但看前面的byte[] 和最后几个是否和保存的时候一样.一般都是保存的时候就损坏了数据.
[/Quote]

谢谢你的回复！
刚才看了一下，前后是有差别的，保存前从byte[255]开始就是一连串的“？”，保存后还不到255就是“？”。不知这个问题如何解决？真是晕啊>>>>>
但在网上搜到的都是这样做的，你们都成功了吗？好孤单！！！