Converting String to Btye[]

in this Line:
<pre lang="vb">bytes = usr</pre>

This is the fullcode

<pre lang="vb">

Private WithEvents verifyControl As DPFP.Gui.Verification.VerificationControl
Private matcher As DPFP.Verification.Verification
Private matchResult As DPFP.Verification.Verification.Result
Private allReaderSerial As String = "00000000-0000-0000-0000-000000000000"
Public template As DPFP.Template

Private userTemplateColumn As String = "Template"
Private userIDColumn As String = "ID"
Dim bytes As Byte()
Private Sub CreateDPControl(ByRef control As DPFP.Gui.Verification.VerificationControl)
Try
control = New DPFP.Gui.Verification.VerificationControl()
control.AutoSizeMode = Windows.Forms.AutoSizeMode.GrowAndShrink
control.Name = "verifyControl"
control.Location = New System.Drawing.Point(0, 0)
control.ReaderSerialNumber = "00000000-0000-0000-0000-000000000000"
control.Visible = True
control.Enabled = True
control.BringToFront()


Me.Controls.Add(control)

Catch ex As Exception
MessageBox.Show("exception")
End Try
End Sub

Private Function ConnectString() As String

Dim connectionString As String
connectionString = "*****************************"

Return connectionString

End Function

Private Sub VerifyBiometric_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
matcher = New Verification.Verification()
matchResult = New Verification.Verification.Result
CreateDPControl(verifyControl)
End Sub



Private Sub verifyControl_OnComplete(ByVal Control As Object, ByVal FeatureSet As DPFP.FeatureSet, ByRef EventHandlerStatus As DPFP.Gui.EventHandlerStatus) Handles verifyControl.OnComplete

Dim dataSet As DataSet = New DataSet()
Dim adapter As SqlDataAdapter = New SqlDataAdapter()
Dim sqlCommand As SqlCommand = New SqlCommand()

Dim ctr = 0
Try

Dim max As Integer = 0


Dim cn As New SqlConnection(ConnectString())
cn.Open()

sqlCommand.CommandText = "Select template from usertbl where username='" + registration.txtusername.Text + "'"
sqlCommand.CommandType = CommandType.Text
sqlCommand.Connection = cn

Dim lrd As SqlDataReader = sqlCommand.ExecuteReader()
Dim usr
While lrd.Read()
usr = lrd("template")
End While


bytes = Nothing
bytes = usr

template = New DPFP.Template()
template.DeSerialize(usr)
'Perform match
matcher.Verify(FeatureSet, template, matchResult)
If matchResult.Verified Then
EventHandlerStatus = Gui.EventHandlerStatus.Success
MsgBox("Verified!")
Me.Hide()
registration.Show()
Else

EventHandlerStatus = Gui.EventHandlerStatus.Failure
MsgBox("Please Try Again!")
End If



Finally

End Try

End Sub</pre>