database - 输入流不是有效的二进制格式。

Question

在下文中，我将类对象“ListViewCereal”序列化到内存流中，然后将内存流的缓冲区存储到 Access 数据库列中。

    If chkSerialize.Checked = True Then
        Dim cereal As New ListViewCereal                                        'class used to store item list views
        Dim bin_form As New BinaryFormatter                                     'used to serialize and deserialize objects
        Dim file_stream As New MemoryStream                                     'serialization stream
        Dim report_row As DataRow = mycallerPreview.previewInst.SerializedDataDataSet.SavedReportLayouts.NewRow

        cereal.prep_cereal(MoveItemListViewClass1, MoveItemListViewClass2, MoveItemListViewClass3)
        bin_form.Serialize(file_stream, cereal)
        builder.Clear()

        'extract buffer and append string representation of each bit to StringBuilder "builder"
        file_stream.Position = 0
        Dim byteArray() As Byte = file_stream.GetBuffer()
        For Each bit As Byte In byteArray
            builder.Append(bit.ToString)
        Next

        report_row("Serialized Data") = builder.ToString 'column storing string rep. of buffer

        builder.Clear()
        builder.Append(txtYear.Text.ToString).Append("-").Append(txtVendor.Text.ToString).Append("-").Append(txtReport.Text.ToString)
        report_row("Report Name") = builder.ToString
        report_row("User Name") = ""                        'TODO:setup login window to track users
        mycallerPreview.previewInst.SerializedDataDataSet.SavedReportLayouts.AddSavedReportLayoutsRow(report_row)
        mycallerPreview.previewInst.TableAdapterManager.UpdateAll(mycallerPreview.previewInst.SerializedDataDataSet)

        file_stream.Close()
        file_stream.Dispose()
        mycallerPreview.Show()
        mycallerPreview.previewInst.Close()
        mycallerPreview.previewInst = Nothing
    Else
        mycallerPreview.Show()
        mycallerPreview.previewInst.Close()
        mycallerPreview.previewInst = Nothing
    End If

在下面的代码中，我尝试通过引用数据库行/列来反序列化类。

       If cmbSavedLayouts.SelectedIndex <> -1 Then

        Dim rep_row As DataRow = mycallerSelect2.select_secInst.SerializedDataDataSet.SavedReportLayouts.NewRow
        rep_row = mycallerSelect2.select_secInst.SerializedDataDataSet.SavedReportLayouts.Rows(cmbSavedLayouts.SelectedIndex)
        Dim str As String = rep_row("Serialized Data").ToString
        Dim temp As Byte() = str.Select(AddressOf Byte.Parse).ToArray
        Dim file_stream As New MemoryStream

        file_stream.Write(temp, 0, temp.Count)
        file_stream.Position = 0
        Dim cereal_views As ListViewCereal = CType(bin_form.Deserialize(file_stream), ListViewCereal)
    End If

当我尝试反序列化 file_stream 时，收到未处理的异常“输入流不是有效的二进制格式”。我对此很陌生，因此不胜感激!

Answer 1

你有几个错误。首先，有这个:

Dim byteArray() As Byte = file_stream.GetBuffer()

缓冲区总是比存储的数据大；有时更大(70-80%!)，所以应该使用 ToArray() 来获取数据。接下来是这样的:

For Each bit As Byte In byteArray
    builder.Append(bit.ToString)
Next

我不知道 builder 是什么，但它看起来像一个 StringBuilder。保存 byteArray 本身并避免任何其他转换是最简单的。但是对于字符串存储，您应该使用可以轻松转换回字节数组的 Base64 字符串:

Dim serData As String = Convert.ToBase64String(memStrm.ToArray())

因此，序列化和存储应该是这样的:

Dim B64Data As String
Using ms As New MemoryStream
    Dim bf As New BinaryFormatter
    bf.Serialize(ms, cereal)
    B64Data = Convert.ToBase64String(ms.ToArray())
End Using

' no idea what this is, just copied it
report_row("Serialized Data") = B64Data 

反序列化是相反的:

' get data, unbox
Dim B64Data = dr.Field(Of String)("Serialized Data")

' I have no idea if these types are correct, just copying them
Dim cereal_views As ListViewCereal
Using ms As New MemoryStream(Convert.FromBase64String(B64Data ))
    Dim bf As New BinaryFormatter
    cereal_views = CType(bf.Deserialize(ms), ListViewCereal)
End Using