Hi, im new trying with bluetooth. Im trying to use Inthehand in vb .net  2005 with a htc. I want to connect to another device, but i got an error: Null reference y the line with ****** next, here is my code, thanks for the atention.

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim BlueC As New BluetoothClient
        Dim BlueI As BluetoothDeviceInfo() = BlueC.DiscoverDevices(6)

        cmbname.DataSource = BlueI
        cmbname.DisplayMember = "DeviceName"

        cmbaddress.DataSource = BlueI
        cmbaddress.DisplayMember = "DeviceAddress"

    End Sub

    Private Sub bconectar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bconectar.Click
        Dim address As New BluetoothAddress(Long.Parse(cmbaddress.Text, Globalization.NumberStyles.HexNumber))
        Dim ep As New BluetoothEndPoint(address, BluetoothService.SerialPort)
        bc.Connect(ep)                                                                            **************************************************
    End Sub                      

Help me, please!

Looks as if bc is not initialised...  Change to:

   Private Sub bconectar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bconectar.Click
        Dim address As BluetoothAddress.Parse(cmbaddress.Text)
        Dim ep As New BluetoothEndPoint(address, BluetoothService.SerialPort)
        Dim bc As New BluetoothClient
        bc.Connect(ep)
    End Sub

Good morning! Thanks for the reply. THAT SOLVE MY PROBLEM. I did declare the BluetoothClient but whitout the word "New". Thank you so much.

Now i have another question: when i try to connect without activating first the bluetooth i have an error. I need to activate it by code. How can i do it??

 Now i activate and diactivate the bluetooth. But i have another problem, when i connect then disconnect and try to connect a second time, doesnt matter witch bluetoothdevice i got the error: InTheHand.Net.Sockets.BluetootClient

My code for connect:

 If br.PrimaryRadio.Mode = RadioMode.PowerOff Then
            Try : br.PrimaryRadio.Mode = RadioMode.Discoverable
            Catch ex As Exception : MsgBox("No se pudo activar el bluetooth")
            End Try
        End If

        Try
            bc.Connect(ep)
        Catch ex As Exception
            MsgBox("No se ha podido conectar " & ex.Message)
            Exit Sub
        End Try
        MsgBox("Se ha conectado")

My code for disconnect:

Try
            bc.Close()
            bc.Dispose()
        Catch ex As Exception
            MsgBox("No se pudo cerrar " & ex.Message)
            Exit Sub
        End Try
        MsgBox("Se ha cerrado")

        Try : br.PrimaryRadio.Mode = RadioMode.PowerOff
        Catch ex As Exception : MsgBox("No se pudo apagar el bluetooth")
        End Try

You need a new BluetoothClient each time.  Add the initialisation of the bc just before you call Connect -- I presume at the moment you are only doing it once each time the program runs.  If that's not the problem copy the whole error here -- including the exception stack trace (e.g. FooBarException: Some Message
  at foo
  at bar)

 Perfect!!

 I change the declaration of the client for this: 

    Dim bc As BluetoothClient

 And add bc=new BluetoothClient before connect.

Thanks a lot!! 

Pleased to hear you got it working. :-)