How to wait for get request without freezing client - vb.net

Question

I have a simple button which sends a get request to retrieve a txt file on my website. Problem is it freezes the application while retrieving the info. How can I make it so the application doesn't freeze while waiting for the result?
Private Sub cmd_ClickMe_Click(sender As Object, e As EventArgs) Handles cmd_ClickMe.Click
Dim request As String = String.Format("http://www.*****/database/test.txt")
Dim webClient As New System.Net.WebClient
Dim result As String = webClient.DownloadString(request)
MessageBox.Show(result)
End Sub
I've also tried the following but it doesn't work (says "webClient.DownloadStringAsync(myUri)" does not produce a value:
Private Sub cmd_ClickMe_Click_1(sender As Object, e As EventArgs) Handles cmd_ClickMe.Click
Dim request As String = String.Format("http://www.****.com/database/test.txt")
Dim webClient As New System.Net.WebClient
Dim myUri As Uri = New Uri(request)
Dim result As String = webClient.DownloadStringAsync(myUri)
MessageBox.Show(result)
End Sub

Answer 1

Use DownloadStringAsync(Uri) instead of the DownloadString(uri).
The DownloadStringAsync method does not block the calling thread.
Here is an example how to use it:
Dim wc As New WebClient
' Specify that you get alerted
' when the download completes.
AddHandler wc.DownloadStringCompleted, AddressOf AlertStringDownloaded
Dim uri As New Uri("http:\\changeMe.com") 'Pass the URL to here. This is just an example
wc.DownloadStringAsync(uri)
End Sub
Public Shared Sub AlertStringDownloaded(ByVal sender As Object, ByVal e As DownloadStringCompletedEventArgs)
' If the string request went as planned and wasn't cancelled:
If e.Cancelled = False AndAlso e.Error Is Nothing Then
Dim myString As String = CStr(e.Result) 'Use e.Result to get the String
MessageBox.Show(myString)
End If
End Sub