How can I display a MessageBox when a website being searched is blocked by host?

[Modulus]

I have an application which adds text to the hosts file from a .txt file full of blacklisted websites.


It works, however, when the website is blocked, I want a Message to come up saying "Website Blocked". This is my code:

 Public Function Initizalize() As String
        Dim systemroot As String
        Dim root As String
        systemroot = Environment.GetEnvironmentVariable("SystemRoot")
        root = (systemroot + "\system32\drivers\etc\hosts")
        Return root
    End Function

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim dir As String
        dir = Me.Initizalize
        Dim systemroot As String
        Dim root As String
        systemroot = Environment.GetEnvironmentVariable("SystemRoot")
        root = (systemroot + "\system32\drivers\etc\hosts")
        Dim line As String
        Dim sr = New StreamReader("whitelistsites.txt")
        line = sr.ReadLine
        Dim filePath = "C:\Windows\System32\drivers\etc\hosts"

        File.WriteAllLines(filePath, File.ReadAllLines(filePath).Where(Function(s) s <> line))
        File.AppendAllText(dir, (Environment.NewLine _
                        + (line + Environment.NewLine)))

        While ((Not (line) Is Nothing) _
                    AndAlso (line <> ""))
            MessageBox.Show(("Appeanding Line: " + line))
            File.AppendAllText(dir, (line + Environment.NewLine))
            line = sr.ReadLine

        End While

        sr.Close()
        MessageBox.Show("Done!")
    End Sub

So, what I'm trying to say, is that when a website is searched [EDITED]FROM[/EDITED] the host file, it goes to the

ERR_CONNECTION_REFUSED

page on Chrome, then, once it goes to that page, I want a MessageBox to appear. Is there a way to do this?

I know, I've mentioned the Initialize code twice, but, I'm just going to leave it. Please comment for any more info. I didn't explain this very well, I know.

Maybe Google provides an API to do this? But what about for ALL browsers?