Proxy Checker

    Imports System.IO
    Imports System.Net
    Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim fo As New OpenFileDialog
    fo.RestoreDirectory = True
    fo.Multiselect = False
    fo.Filter = "txt files (*.txt)|*.txt"
    fo.FilterIndex = 1
    fo.ShowDialog()
    If (Not fo.FileName = Nothing) Then
    Dim proxies As New List(Of String)
    Using sr As New StreamReader(fo.FileName)
    While sr.Peek <> -1
    proxies.Add(sr.ReadLine())
    End While
    End Using
    Dim myProxy As WebProxy
    For Each proxy As String In proxies
    Try
    myProxy = New WebProxy(proxy)
    Dim r As HttpWebRequest = HttpWebRequest.Create("http://www.google.com")
    r.UserAgent = "Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.2 Safari/537.36"
    r.Timeout = 3000
    r.Proxy = myProxy
    Dim re As HttpWebResponse = r.GetResponse()
    ListBox1.Items.Add("Working Proxy: " & proxy)
    Catch ex As Exception
    ListBox1.Items.Add("Unresponsive Proxy: " & proxy)
    End Try
    Next
    End If
    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    If (ListBox1.Items.Count > 0) Then
    Dim fs As New SaveFileDialog
    fs.RestoreDirectory = True
    fs.Filter = "txt files (*.txt)|*.txt"
    fs.FilterIndex = 1
    fs.ShowDialog()
    If Not (fs.FileName = Nothing) Then
    Using sw As New StreamWriter(fs.FileName)
    For Each line As String In ListBox1.Items
    sw.WriteLine(line)
    Next
    End Using
    End If
    End If
    End Sub

    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
    If (ListBox1.Items.Count > 0) Then
    Dim fs As New SaveFileDialog
    fs.RestoreDirectory = True
    fs.Filter = "txt files (*.txt)|*.txt"
    fs.FilterIndex = 1
    fs.ShowDialog()
    If Not (fs.FileName = Nothing) Then
    Using sw As New StreamWriter(fs.FileName)
    For Each line As String In ListBox1.Items
    If (line.StartsWith("Working Proxy: ")) Then sw.WriteLine(line)
    Next
    End Using
    End If
    End If
    End Sub
    End Class