Public Class MyCmb

    Dim NC As Control = Nothing
    Private Sub MyCmb_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
        If e.KeyCode = Keys.Enter Then
            If Me.NC Is Nothing Then
                SendKeys.Send("{TAB}")
            Else
                NC.Focus()
            End If
        End If
    End Sub
    Public Property NectControl() As Control
        Get
            Return NC
        End Get
        Set(ByVal value As Control)
            NC = value
        End Set
    End Property

End Class