Question

Reading binary data out of the database, and I need to convert it back into a Digital Persona fingerprint template. I’m not familiar with serialization and deserialization, so I could use a bit of help. Here’s what I tried:

Dim rsBioData As SqlDataReader = SQL.ExecuteReader
Dim byteTemplate As Byte
Dim memStreamTemplate As MemoryStream
If rsBioData.HasRows Then
    While rsBioData.Read
        byteTemplate = rsBioData("BiometricData")
        memStreamTemplate = New MemoryStream(byteTemplate)
        Me.Template = DirectCast(template.DeSerialize(memStreamTemplate), DPFP.Template)
    End While
End If
rsBioData.Close()

I receive an error that template.DeSerialize(memStreamTemplate) does not create a value.

For kicks, here’s how I serialized the object to place it into the database. I assume this part is working, since the binary data shows up in SQL server–just can’t read it back out to see.

Dim str As New MemoryStream
Enroller.Template.Serialize(str)
Dim serializedTemplate As Byte() = str.ToArray()
SQL.Parameters.AddWithValue("biometricData", serializedTemplate)

Thanks

Answer 1

Here’s how I was finally able to do it. I was SO close the first time around.

            byteTemplate = rsBioData("BiometricData")
            memStreamTemplate = New MemoryStream(byteTemplate)
            Me.Template.DeSerialize(memStreamTemplate)