Imports System.ComponentModel

Public Class ConnectionValidater
    Inherits Component
    Public Event GotResult(ByVal address As String, ByVal success As Boolean)

    Public Structure connectattempt
        Public client As System.Net.Sockets.TcpClient
        Public address As String
    End Structure

    Private Sub OnConnect(ByVal value As System.IAsyncResult)
        Dim att As connectattempt = value.AsyncState

        Dim success As Boolean
        Try
            Dim s As System.Net.Sockets.NetworkStream = att.client.GetStream
            success = s.CanRead
            att.client.EndConnect(value)
            att.client.Close()
            s.Close()
        Catch
            success = False
        End Try
        RaiseEvent GotResult(att.address, success)
    End Sub

    Public Sub BeginValidating(ByVal address As String)
        Dim c As New connectattempt
        c.client = New System.Net.Sockets.TcpClient()
        c.address = address
        Dim port As Integer = 25565
        If address.Contains(":") Then
            Dim ps As String = address.Remove(0, address.IndexOf(":") + 1)
            If Not Integer.TryParse(ps, port) Then port = 25565
            address = address.Remove(address.Length - ps.Length - 1)
        End If
        c.client.BeginConnect(address, port, New System.AsyncCallback(AddressOf OnConnect), c)
    End Sub
End Class