Question

我在访问数据库中保存了一张图片，一切正常，但是当我想要检索它时，我不能。

这是我将图片保存在数据库中的代码。我需要代码将其检索到vb.net中的PictureBox

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
     Try

        OpenFileDialog1.Filter = "image file (*.jpg, *.bmp, *.png) | *.jpg; *.bmp; *.png| all files (*.*) | *.* "
         If OpenFileDialog1.ShowDialog <> Windows.Forms.DialogResult.Cancel Then
             PictureBox1.Image = Image.FromFile(OpenFileDialog1.FileName)
             PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage

         End If
     Catch ex As Exception

     End Try
 End Sub

 Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
     Dim fsreader As New FileStream(OpenFileDialog1.FileName, FileMode.Open, FileAccess.Read)

     Dim breader As New BinaryReader(fsreader)

     Dim imgbuffer(fsreader.Length) As Byte
     breader.Read(imgbuffer, 0, fsreader.Length)
     fsreader.Close()

     con.ConnectionString = "provider=microsoft.ace.oledb.12.0; data source = |datadirectory|\test.accdb;"
     con.Open()
     Dim sql As String
     sql = "insert into TS Values(" & TextBox1.Text & ",'" & imgbuffer.Length & "')"
     Dim cmd As New OleDbCommand(sql, con)
     cmd.ExecuteNonQuery()
     cmd.Dispose()
     con.Close()
 End Sub

Answer 1

但我不认为您是以二进制格式保存图像，甚至您还没有将此最新更新放在此查询上。所以我假设你已经以二进制形式保存了图像我们来看看。

我假设如果您已将图像保存在“长二进制数据”中，则必须使用图像ID来调用该图像。或者，更好的是，如果您使用学生编号现在你在这里做的只是制作一个TextBox（即Textbox1）。然后按照代码。

首先打开一个连接然后：

Try
    Dim command As New OleDbCommand("SELECT Image FROM Table WHERE Rollno ='" & textbox1.Text & "'", myconnection)
    command.Parameters.AddWithValue("@Rollno", Textbox1.Text)
    Dim pictureData As Byte() = DirectCast(command.ExecuteScalar(), Byte())

    myconnection.Close()
    command.Dispose()
    Dim stream As New IO.MemoryStream(pictureData)
    Me.PictureBox1.Image = Image.FromStream(stream)'See in this picturebox1 you're showing the Image.
    '' NOTE: don't dispose the stream!!
Catch ex As Exception
    Label3.ForeColor = Color.Red
    Label3.Text = "The Given Rollno has not found in the database"
    Return
End Try

从访问数据库中检索图片

1 个答案: