輸入流不是有效的二進制格式。

Question

在下面我將序列化類對象「ListViewCereal」到內存流中，然後將內存流的緩衝區存儲到訪問數據庫列。

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 

在下面的代碼中，我嘗試通過引用數據庫行/列來反序列化類。

 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 

我收到未處理的異常「輸入流不是有效的二進制格式」當我嘗試反序列化file_stream。我相當新，所以任何幫助表示讚賞！

Answer 1

您有幾個錯誤。首先是這樣的：

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

緩衝區總是大於存儲的數據;有時要大得多（70-80％！），所以應該使用ToArray()來獲取數據。接下來是這樣的：

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

我不知道什麼是builder，但它看起來像一個StringBuilder。保存byteArray本身並避免任何其他轉換是最簡單的。對於字符串存儲但是，你應該使用Base64編碼字符串，它可以很容易地轉換回一個字節數組：

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

因此，序列化和存儲應該是這樣的：

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 

反序列化將是反向：

' 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