Vb.net 如何从数据库中检索指纹的序列化模板？

我使用的是

digitalpersona u.are.u 4500

指纹阅读器

这是我用来将指纹模板保存到数据库的代码：

    Dim str As New MemoryStream
    Enroller.Template.Serialize(str)
    Dim serializedTemplate As Byte() = str.ToArray()
    Dim bytes() as Byte = serializedTemplate
    comm.Parameters.AddWithValue("@Emp_FPrint", bytes)

问题是，当我尝试从数据库检索指纹并对其进行反序列化时，出现以下错误：

从类型“Byte（）”到类型“Byte”的转换无效

这是我用来检索和反序列化指纹的代码：

    Sub OnComplete(ByVal Capture As Object, ByVal ReaderSerialNumber As String, ByVal Sample As DPFP.Sample) Implements DPFP.Capture.EventHandler.OnComplete
      MakeReport("The fingerprint sample was captured.")
      SetPrompt("Scan the same fingerprint again.")
      Process(Sample)

      CheckTemplate()
      If ds1MaxRow > 0 Then
        For i = 0 To ds1MaxRow - 1
            '  byteArray = CType(ds1VerifyFPrintp.Tables("TestImage").Rows(i).Item(1), Byte())
            con1 = New SqlConnection
            con1.ConnectionString = "Data Source=ERSERVER;Initial Catalog=Timekeeping;User ID=sa;Password=sa"
            Dim thequery As String = "Select Emp_FPrint from TestImage "
            con1.Open()
            Dim cmd As SqlCommand = New SqlCommand(thequery, con1)
            Dim rsBioData As SqlDataReader = cmd.ExecuteReader

            Dim byteTemplate As Byte
            Dim memStreamTemplate As MemoryStream
            If rsBioData.HasRows Then
                While rsBioData.Read
                    byteTemplate = rsBioData("Emp_FPrint")      ''''''''ERROR HERE :   Conversion from type 'Byte()' to type 'Byte' is not valid. '''''''
                    memStreamTemplate = New MemoryStream(byteTemplate)     
                    Me.Template.DeSerialize(memStreamTemplate)
                End While
            End If       
            '''''''STUCK UNTO THIS LINE''''''''''

            Dim features As DPFP.FeatureSet = ExtractFeatures(Sample, DPFP.Processing.DataPurpose.Verification)

            ' Check quality of the sample and start verification if it's good
            If Not features Is Nothing Then
                ' Compare the feature set with our template
                Dim result As DPFP.Verification.Verification.Result = New DPFP.Verification.Verification.Result()
                Verificator.Verify(features, Template, result)
                '  UpdateStatus(result.FARAchieved)
                If result.Verified Then
                    MakeReport("The fingerprint was VERIFIED.")
                Else
                    MakeReport("The fingerprint was NOT VERIFIED.")
                End If
            End If

        Next i
    End If
 End Sub

试试这个

Dim cmd作为新的MySqlCommand（“从employeefp中选择*，康涅狄格州） 作为MySqlDataReader=cmd.ExecuteReader（）的Dim rdr

---

尝试将“

byteTemplate

声明为

byteTemplate（）

我已经尝试过了，但仍停留在第行：Me.Template.DeSerialize（memStreamTemplate）中，并出现以下错误：“System.NullReferenceException”其他信息：对象引用未设置为对象的实例。是否调试了代码？它是否在byteTemplate中获取任何信息？检查并检查我已经检查了byteTemplate（），它的长度为“275124”。

While (rdr.Read())
    Dim MemStream As IO.MemoryStream
    Dim fpBytes As Byte()

    fpBytes = rdr("FP")
    MemStream = New IO.MemoryStream(fpBytes)

    Dim templa8 As DPFP.Template = New DPFP.Template()
    templa8.DeSerialize(MemStream)

    Dim tmpObj As New AppData
    tmpObj.No = rdr("No").ToString()
    tmpObj.Template = templa8
    FPList.Add(tmpObj)
End While