Question

我正在努力：

1）扫描图像并将其插入内存流。

2）在picturebox1中显示。

3）将picturebox1图像读入内存流并将其保存到oledb。

这是我的代码：

1st）通过WIA Dialog扫描并将图像插入memorystream，然后在picturebox1中显示：

 Try

   Dim CD As New WIA.CommonDialog

   Dim F As WIA.ImageFile = CD.ShowAcquireImage(WIA.WiaDeviceType.ScannerDeviceType)

   If F IsNot Nothing Then

            Dim MStream As IO.MemoryStream = Nothing
            Try
                'Convert the raw scanner output into a byte array
                Dim ImageBytes() As Byte = DirectCast(F.FileData.BinaryData, Byte())
                'Read the image data bytes into a MemoryStream
                MStream = New IO.MemoryStream(ImageBytes)
                PictureBox1.Image = System.Drawing.Image.FromStream(MStream)
            Catch ex As Exception
                MsgBox("An error occurred:  " & ex.Message, MsgBoxStyle.Critical)
            End Try
            If MStream IsNot Nothing Then MStream.Dispose()
   End If

  Catch ex As Exception
      MsgBox(ex.message, MsgBoxStyle.Critical)
  End Try

这很完美。

问题即将来临，

2nd）将picturebox1中的图像读入新的内存流，然后将其保存到oledb：

If conn.State = ConnectionState.Closed Then
        conn.ConnectionString = connstring
        conn.Open()

            'Reading image from picturebox1 and then insert it to a new memorystream.
            Dim arrImage() As Byte
            Dim myMs As New IO.MemoryStream
            PictureBox1.Image.Save(myMs, System.Drawing.Imaging.ImageFormat.Jpeg)
            arrImage = myMs.GetBuffer

            'Now save image to oledb from the memorystream.
            Dim query As String = "INSERT INTO Guestinfo ([IDImage]) VALUES (@IDImage)"
            Dim command As New OleDbCommand
            With command
                .CommandText = query
                .Parameters.Add("@IDImage", OleDb.OleDbType.Binary).Value = arrImage
                .Connection = conn
                .ExecuteNonQuery()
            End With
            MsgBox("Saved Successfully!", MsgBoxStyle.Information)
            conn.Close()
            ListView1.Items.Clear()
            loadlistview()
            Me.Close()
 End If

错误在这一行：

PictureBox1.Image.Save(myMs, System.Drawing.Imaging.ImageFormat.Jpeg)

我可能会看到这个错误，因为在扫描过程中我们将图像转换为字节数组以将其放入内存流中，但在阅读过程中，我们试图将图片框图像作为Jpeg读入内存流。

我可以看到，作为Visualbasic的初学者，我的任何帮助都会受到赞赏。

Answer 1

根据Image.FromStream的文档，流必须在Image的生命周期内保持打开状态，但您要在此行中处理流：

If MStream IsNot Nothing Then MStream.Dispose()

尝试从第一个代码块中删除该行。

我认为MemoryStream应该在某个时候被处理掉，但是PictureBox和Image类可能会为你处理。{1}}和Dispose类。否则，您可能必须在表单关闭时添加{{1}}调用。

将图像保存到内存流错误

1 个答案: